Alzheimer's & Cognition

TOPLINE:

The risk for dementia before age 90 years was significantly higher among people with a history of proton pump inhibitor (PPI) use and was highest among those diagnosed before age 70 years regardless of when PPI treatment was initiated.

METHODOLOGY:

• Researchers used four Danish registries to collect data on dementia diagnoses and prescription PPI use among 1,983,785 individuals aged 60-75 years between 2000 and 2018.
• The median follow-up time was 10.3 years.

TAKEAWAY:

• There were 99,384 (5.0%) cases of all-cause dementia during follow-up, with a median age of diagnosis of 79 years.
• Twenty-one-point-two percent of dementia cases and 18.9% of controls reported a history of PPI use.
• Risk for all-cause dementia before age 90 years was 36% higher with PPI use in people aged 60-69 years at baseline (adjusted incidence rate ratio, 1.36; 95% confidence interval, 1.29-1.43) and 6% higher in those who were age 80-89 years at baseline (aIRR, 1.06; 95% CI, 1.03-1.09).
• Investigators found significant increased dementia risk before age 90 years with PPI use regardless of when PPI treatment began and found no link between PPI use and dementia diagnoses after age 90 years.

IN PRACTICE:

“The association between PPI use and dementia was unambiguously largest among the youngest cases of dementia, potentially suggestive of a critical window of exposure where midlife PPI use affects dementia risk to a larger degree compared to late-life use,” the authors wrote. “Further, the finding could signify a declining impact of individual risk factors with advancing age owing to lengthy ongoing neuropathological processes.”

SOURCE:

Lead author of the study was Nelsan Pourhadi, MD, Danish Dementia Research Centre, department of neurology, Copenhagen University Hospital–Rigshospitalet. It was published online in Alzheimer’s and Dementia.

LIMITATIONS:

The study did not include data on PPI prescriptions before 1995, over-the-counter PPI use, and in-hospital intravenous use of PPI during the study period.

DISCLOSURES:

The study was funded by the Danish Ministry of Health. The authors reported no relevant conflicts.

A version of this article first appeared on Medscape.com.

TOPLINE:

The risk for dementia before age 90 years was significantly higher among people with a history of proton pump inhibitor (PPI) use and was highest among those diagnosed before age 70 years regardless of when PPI treatment was initiated.

METHODOLOGY:

• Researchers used four Danish registries to collect data on dementia diagnoses and prescription PPI use among 1,983,785 individuals aged 60-75 years between 2000 and 2018.
• The median follow-up time was 10.3 years.

TAKEAWAY:

• There were 99,384 (5.0%) cases of all-cause dementia during follow-up, with a median age of diagnosis of 79 years.
• Twenty-one-point-two percent of dementia cases and 18.9% of controls reported a history of PPI use.
• Risk for all-cause dementia before age 90 years was 36% higher with PPI use in people aged 60-69 years at baseline (adjusted incidence rate ratio, 1.36; 95% confidence interval, 1.29-1.43) and 6% higher in those who were age 80-89 years at baseline (aIRR, 1.06; 95% CI, 1.03-1.09).
• Investigators found significant increased dementia risk before age 90 years with PPI use regardless of when PPI treatment began and found no link between PPI use and dementia diagnoses after age 90 years.

IN PRACTICE:

“The association between PPI use and dementia was unambiguously largest among the youngest cases of dementia, potentially suggestive of a critical window of exposure where midlife PPI use affects dementia risk to a larger degree compared to late-life use,” the authors wrote. “Further, the finding could signify a declining impact of individual risk factors with advancing age owing to lengthy ongoing neuropathological processes.”

SOURCE:

Lead author of the study was Nelsan Pourhadi, MD, Danish Dementia Research Centre, department of neurology, Copenhagen University Hospital–Rigshospitalet. It was published online in Alzheimer’s and Dementia.

LIMITATIONS:

The study did not include data on PPI prescriptions before 1995, over-the-counter PPI use, and in-hospital intravenous use of PPI during the study period.

DISCLOSURES:

The study was funded by the Danish Ministry of Health. The authors reported no relevant conflicts.

A version of this article first appeared on Medscape.com.

TOPLINE:

The risk for dementia before age 90 years was significantly higher among people with a history of proton pump inhibitor (PPI) use and was highest among those diagnosed before age 70 years regardless of when PPI treatment was initiated.

METHODOLOGY:

• Researchers used four Danish registries to collect data on dementia diagnoses and prescription PPI use among 1,983,785 individuals aged 60-75 years between 2000 and 2018.
• The median follow-up time was 10.3 years.

TAKEAWAY:

• There were 99,384 (5.0%) cases of all-cause dementia during follow-up, with a median age of diagnosis of 79 years.
• Twenty-one-point-two percent of dementia cases and 18.9% of controls reported a history of PPI use.
• Risk for all-cause dementia before age 90 years was 36% higher with PPI use in people aged 60-69 years at baseline (adjusted incidence rate ratio, 1.36; 95% confidence interval, 1.29-1.43) and 6% higher in those who were age 80-89 years at baseline (aIRR, 1.06; 95% CI, 1.03-1.09).
• Investigators found significant increased dementia risk before age 90 years with PPI use regardless of when PPI treatment began and found no link between PPI use and dementia diagnoses after age 90 years.

IN PRACTICE:

“The association between PPI use and dementia was unambiguously largest among the youngest cases of dementia, potentially suggestive of a critical window of exposure where midlife PPI use affects dementia risk to a larger degree compared to late-life use,” the authors wrote. “Further, the finding could signify a declining impact of individual risk factors with advancing age owing to lengthy ongoing neuropathological processes.”

SOURCE:

Lead author of the study was Nelsan Pourhadi, MD, Danish Dementia Research Centre, department of neurology, Copenhagen University Hospital–Rigshospitalet. It was published online in Alzheimer’s and Dementia.

LIMITATIONS:

The study did not include data on PPI prescriptions before 1995, over-the-counter PPI use, and in-hospital intravenous use of PPI during the study period.

DISCLOSURES:

The study was funded by the Danish Ministry of Health. The authors reported no relevant conflicts.

A version of this article first appeared on Medscape.com.

TOPLINE:

People with a history of depression or stress were significantly more likely to be diagnosed with mild cognitive impairment (MCI) or Alzheimer’s disease (AD) later in life compared with those without either condition, a new study found.

METHODOLOGY:

• Longitudinal cohort study of 1,362,548 people with records in the Region Stockholm administrative health care database with a diagnosis of stress-induced exhaustion disorder (SED), depression, or both between 2012 and 2013.
• Cohort followed for diagnosis of MCI or AD between 2014 and 2022.

TAKEAWAY:

• SED diagnosed in 0.3%, depression in 2.9% and both SED and depression in 0.1%
• Compared with people without SED or depression, AD risk was more than double in patients with SED (adjusted odds ratio [aOR], 2.45; 99% confidence interval [CI], 1.22-4.91) or depression (aOR, 2.32; 99% CI, 1.85-2.90) and four times higher in patients with both SED and depression (aOR, 4.00; 99% CI, 1.67-9.58)
• Risk for MCI was also higher in people with SED (aOR, 1.87; 99% CI,1.20-2.91), depression (aOR, 2.85; 99% CI, 2.53-3.22) or both SED and depression (aOR, 3.87; 99% CI, 2.39-6.27) vs patients with no history of SED or depression.
• Only patients with depression had a higher risk for another dementia type (aOR, 2.39; 99% CI, 1.92-2.96).

IN PRACTICE:

“Future studies should examine the possibility that symptoms of depression and/or chronic stress could be prodromal symptoms of dementia rather than risk factors,” study authors wrote.

SOURCE:

The study was conducted by Johanna Wallensten, doctoral student, department of clinical sciences, Danderyd Hospital, Stockholm, and colleagues and funded by the Karolinska Institute. It was published online in Alzheimer’s Research and Therapy.

LIMITATIONS:

Use of a health care registry could have led to over- or underestimation of depression, MCI and AD. The study probably captures most people with depression but not most people with depressive symptoms.

DISCLOSURES:

The authors reported no relevant conflicts.

A version of this article appeared on Medscape.com.

TOPLINE:

People with a history of depression or stress were significantly more likely to be diagnosed with mild cognitive impairment (MCI) or Alzheimer’s disease (AD) later in life compared with those without either condition, a new study found.

METHODOLOGY:

• Longitudinal cohort study of 1,362,548 people with records in the Region Stockholm administrative health care database with a diagnosis of stress-induced exhaustion disorder (SED), depression, or both between 2012 and 2013.
• Cohort followed for diagnosis of MCI or AD between 2014 and 2022.

TAKEAWAY:

• SED diagnosed in 0.3%, depression in 2.9% and both SED and depression in 0.1%
• Compared with people without SED or depression, AD risk was more than double in patients with SED (adjusted odds ratio [aOR], 2.45; 99% confidence interval [CI], 1.22-4.91) or depression (aOR, 2.32; 99% CI, 1.85-2.90) and four times higher in patients with both SED and depression (aOR, 4.00; 99% CI, 1.67-9.58)
• Risk for MCI was also higher in people with SED (aOR, 1.87; 99% CI,1.20-2.91), depression (aOR, 2.85; 99% CI, 2.53-3.22) or both SED and depression (aOR, 3.87; 99% CI, 2.39-6.27) vs patients with no history of SED or depression.
• Only patients with depression had a higher risk for another dementia type (aOR, 2.39; 99% CI, 1.92-2.96).

IN PRACTICE:

“Future studies should examine the possibility that symptoms of depression and/or chronic stress could be prodromal symptoms of dementia rather than risk factors,” study authors wrote.

SOURCE:

The study was conducted by Johanna Wallensten, doctoral student, department of clinical sciences, Danderyd Hospital, Stockholm, and colleagues and funded by the Karolinska Institute. It was published online in Alzheimer’s Research and Therapy.

LIMITATIONS:

Use of a health care registry could have led to over- or underestimation of depression, MCI and AD. The study probably captures most people with depression but not most people with depressive symptoms.

DISCLOSURES:

The authors reported no relevant conflicts.

A version of this article appeared on Medscape.com.

TOPLINE:

People with a history of depression or stress were significantly more likely to be diagnosed with mild cognitive impairment (MCI) or Alzheimer’s disease (AD) later in life compared with those without either condition, a new study found.

METHODOLOGY:

• Longitudinal cohort study of 1,362,548 people with records in the Region Stockholm administrative health care database with a diagnosis of stress-induced exhaustion disorder (SED), depression, or both between 2012 and 2013.
• Cohort followed for diagnosis of MCI or AD between 2014 and 2022.

TAKEAWAY:

• SED diagnosed in 0.3%, depression in 2.9% and both SED and depression in 0.1%
• Compared with people without SED or depression, AD risk was more than double in patients with SED (adjusted odds ratio [aOR], 2.45; 99% confidence interval [CI], 1.22-4.91) or depression (aOR, 2.32; 99% CI, 1.85-2.90) and four times higher in patients with both SED and depression (aOR, 4.00; 99% CI, 1.67-9.58)
• Risk for MCI was also higher in people with SED (aOR, 1.87; 99% CI,1.20-2.91), depression (aOR, 2.85; 99% CI, 2.53-3.22) or both SED and depression (aOR, 3.87; 99% CI, 2.39-6.27) vs patients with no history of SED or depression.
• Only patients with depression had a higher risk for another dementia type (aOR, 2.39; 99% CI, 1.92-2.96).

IN PRACTICE:

“Future studies should examine the possibility that symptoms of depression and/or chronic stress could be prodromal symptoms of dementia rather than risk factors,” study authors wrote.

SOURCE:

The study was conducted by Johanna Wallensten, doctoral student, department of clinical sciences, Danderyd Hospital, Stockholm, and colleagues and funded by the Karolinska Institute. It was published online in Alzheimer’s Research and Therapy.

LIMITATIONS:

Use of a health care registry could have led to over- or underestimation of depression, MCI and AD. The study probably captures most people with depression but not most people with depressive symptoms.

DISCLOSURES:

The authors reported no relevant conflicts.

A version of this article appeared on Medscape.com.

Two antiamyloid drugs were recently approved by the Food and Drug Administration for treating early-stage Alzheimer’s disease (AD). In trials of both lecanemab (Leqembi) and donanemab, a long-held neuropharmacologic dream was realized: Most amyloid plaques – the primary pathologic marker for AD – were eliminated from the brains of patients with late pre-AD or early AD.

Implications for the amyloid hypothesis

The reduction of amyloid plaques has been argued by many scientists and clinical authorities to be the likely pharmacologic solution for AD. These trials are appropriately viewed as a test of the hypothesis that amyloid bodies are a primary cause of the neurobehavioral symptoms we call AD.

In parallel with that striking reduction in amyloid bodies, drug-treated patients had an initially slower progression of neurobehavioral decline than did placebo-treated control patients. That slowing in symptom progression was accompanied by a modest but statistically significant difference in neurobehavioral ability. After several months in treatment, the rate of decline again paralleled that recorded in the control group. The sustained difference of about a half point on cognitive assessment scores separating treatment and control participants was well short of the 1.5-point difference typically considered clinically significant.

A small number of unexpected and unexplained deaths occurred in the treatment groups. Brain swelling and/or micro-hemorrhages were seen in 20%-30% of treated individuals. Significant brain shrinkage was recorded. These adverse findings are indicative of drug-induced trauma in the target organ for these drugs (i.e., the brain) and were the basis for a boxed warning label for drug usage. Antiamyloid drug treatment was not effective in patients who had higher initial numbers of amyloid plaques, indicating that these drugs would not measurably help the majority of AD patients, who are at more advanced disease stages.

These drugs do not appear to be an “answer” for AD. A modest delay in progression does not mean that we’re on a path to a “cure.” Treatment cost estimates are high – more than $80,000 per year. With requisite PET exams and high copays, patient accessibility issues will be daunting.

Of note, in my view, the trials of these drugs do not support the hypothesis that amyloid is the primary neuropathologic agent underlying the progressive neurobehavioral decline in AD. To the contrary, they add strong support for the counterargument that the emergence of amyloid plaques is an effect and not a fundamental cause of that progressive loss of neurologic function that we ultimately define as “Alzheimer’s disease.”
 

Time to switch gears

The more obvious path to winning the battle against this human scourge is prevention. A recent analysis published in The Lancet argued that about 40% of AD and other dementias are potentially preventable. I disagree. I believe that 80%-90% of prospective cases can be substantially delayed or prevented. Studies have shown that progression to AD or other dementias is driven primarily by the progressive deterioration of organic brain health, expressed by the loss of what psychologists have termed “cognitive reserve.” Cognitive reserve is resilience arising from active brain usage, akin to physical resilience attributable to a physically active life. Scientific studies have shown us that an individual’s cognitive resilience (reserve) is a greater predictor of risk for dementia than are amyloid plaques – indeed, greater than any combination of pathologic markers in dementia patients.

Building up cognitive reserve

It’s increasingly clear to this observer that cognitive reserve is synonymous with organic brain health. The primary factors that underlie cognitive reserve are processing speed in the brain, executive control, response withholding, memory acquisition, reasoning, and attention abilities. Faster, more accurate brains are necessarily more physically optimized. They necessarily sustain brain system connectivity. They are necessarily healthier. Such brains bear a relatively low risk of developing AD or other dementias, just as physically healthier bodies bear a lower risk of being prematurely banished to semi-permanent residence in an easy chair or a bed.

Brain health can be sustained by deploying inexpensive, self-administered, app-based assessments of neurologic performance limits, which inform patients and their medical teams about general brain health status. These assessments can help doctors guide their patients to adopt more intelligent brain-healthy lifestyles, or direct them to the “brain gym” to progressively exercise their brains in ways that contribute to rapid, potentially large-scale, rejuvenating improvements in physical and functional brain health.

Randomized controlled trials incorporating different combinations of physical exercise, diet, and cognitive training have recorded significant improvements in physical and functional neurologic status, indicating substantially advanced brain health. Consistent moderate-to-intense physical exercise, brain- and heart-healthy eating habits, and, particularly, computerized brain training have repeatedly been shown to improve cognitive function and physically rejuvenate the brain. With cognitive training in the right forms, improvements in processing speed and other measures manifest improving brain health and greater safety.

In the National Institutes of Health–funded ACTIVE study with more than 2,800 older adults, just 10-18 hours of a specific speed of processing training (now part of BrainHQ, a program that I was involved in developing) reduced the probability of a progression to dementia over the following 10 years by 29%, and by 48% in those who did the most training.

This approach is several orders of magnitude less expensive than the pricey new AD drugs. It presents less serious issues of accessibility and has no side effects. It delivers far more powerful therapeutic benefits in older normal and at-risk populations.

Sustained wellness supporting prevention is the far more sensible medical way forward to save people from AD and other dementias – at a far lower medical and societal cost.

Dr. Merzenich is professor emeritus, department of neuroscience, University of California, San Francisco. He reported conflicts of interest with Posit Science, Stronger Brains, and the National Institutes of Health.

A version of this article first appeared on Medscape.com.

Two antiamyloid drugs were recently approved by the Food and Drug Administration for treating early-stage Alzheimer’s disease (AD). In trials of both lecanemab (Leqembi) and donanemab, a long-held neuropharmacologic dream was realized: Most amyloid plaques – the primary pathologic marker for AD – were eliminated from the brains of patients with late pre-AD or early AD.

Implications for the amyloid hypothesis

The reduction of amyloid plaques has been argued by many scientists and clinical authorities to be the likely pharmacologic solution for AD. These trials are appropriately viewed as a test of the hypothesis that amyloid bodies are a primary cause of the neurobehavioral symptoms we call AD.

In parallel with that striking reduction in amyloid bodies, drug-treated patients had an initially slower progression of neurobehavioral decline than did placebo-treated control patients. That slowing in symptom progression was accompanied by a modest but statistically significant difference in neurobehavioral ability. After several months in treatment, the rate of decline again paralleled that recorded in the control group. The sustained difference of about a half point on cognitive assessment scores separating treatment and control participants was well short of the 1.5-point difference typically considered clinically significant.

A small number of unexpected and unexplained deaths occurred in the treatment groups. Brain swelling and/or micro-hemorrhages were seen in 20%-30% of treated individuals. Significant brain shrinkage was recorded. These adverse findings are indicative of drug-induced trauma in the target organ for these drugs (i.e., the brain) and were the basis for a boxed warning label for drug usage. Antiamyloid drug treatment was not effective in patients who had higher initial numbers of amyloid plaques, indicating that these drugs would not measurably help the majority of AD patients, who are at more advanced disease stages.

These drugs do not appear to be an “answer” for AD. A modest delay in progression does not mean that we’re on a path to a “cure.” Treatment cost estimates are high – more than $80,000 per year. With requisite PET exams and high copays, patient accessibility issues will be daunting.

Of note, in my view, the trials of these drugs do not support the hypothesis that amyloid is the primary neuropathologic agent underlying the progressive neurobehavioral decline in AD. To the contrary, they add strong support for the counterargument that the emergence of amyloid plaques is an effect and not a fundamental cause of that progressive loss of neurologic function that we ultimately define as “Alzheimer’s disease.”
 

Time to switch gears

The more obvious path to winning the battle against this human scourge is prevention. A recent analysis published in The Lancet argued that about 40% of AD and other dementias are potentially preventable. I disagree. I believe that 80%-90% of prospective cases can be substantially delayed or prevented. Studies have shown that progression to AD or other dementias is driven primarily by the progressive deterioration of organic brain health, expressed by the loss of what psychologists have termed “cognitive reserve.” Cognitive reserve is resilience arising from active brain usage, akin to physical resilience attributable to a physically active life. Scientific studies have shown us that an individual’s cognitive resilience (reserve) is a greater predictor of risk for dementia than are amyloid plaques – indeed, greater than any combination of pathologic markers in dementia patients.

Building up cognitive reserve

It’s increasingly clear to this observer that cognitive reserve is synonymous with organic brain health. The primary factors that underlie cognitive reserve are processing speed in the brain, executive control, response withholding, memory acquisition, reasoning, and attention abilities. Faster, more accurate brains are necessarily more physically optimized. They necessarily sustain brain system connectivity. They are necessarily healthier. Such brains bear a relatively low risk of developing AD or other dementias, just as physically healthier bodies bear a lower risk of being prematurely banished to semi-permanent residence in an easy chair or a bed.

Brain health can be sustained by deploying inexpensive, self-administered, app-based assessments of neurologic performance limits, which inform patients and their medical teams about general brain health status. These assessments can help doctors guide their patients to adopt more intelligent brain-healthy lifestyles, or direct them to the “brain gym” to progressively exercise their brains in ways that contribute to rapid, potentially large-scale, rejuvenating improvements in physical and functional brain health.

Randomized controlled trials incorporating different combinations of physical exercise, diet, and cognitive training have recorded significant improvements in physical and functional neurologic status, indicating substantially advanced brain health. Consistent moderate-to-intense physical exercise, brain- and heart-healthy eating habits, and, particularly, computerized brain training have repeatedly been shown to improve cognitive function and physically rejuvenate the brain. With cognitive training in the right forms, improvements in processing speed and other measures manifest improving brain health and greater safety.

In the National Institutes of Health–funded ACTIVE study with more than 2,800 older adults, just 10-18 hours of a specific speed of processing training (now part of BrainHQ, a program that I was involved in developing) reduced the probability of a progression to dementia over the following 10 years by 29%, and by 48% in those who did the most training.

This approach is several orders of magnitude less expensive than the pricey new AD drugs. It presents less serious issues of accessibility and has no side effects. It delivers far more powerful therapeutic benefits in older normal and at-risk populations.

Sustained wellness supporting prevention is the far more sensible medical way forward to save people from AD and other dementias – at a far lower medical and societal cost.

Dr. Merzenich is professor emeritus, department of neuroscience, University of California, San Francisco. He reported conflicts of interest with Posit Science, Stronger Brains, and the National Institutes of Health.

A version of this article first appeared on Medscape.com.

Two antiamyloid drugs were recently approved by the Food and Drug Administration for treating early-stage Alzheimer’s disease (AD). In trials of both lecanemab (Leqembi) and donanemab, a long-held neuropharmacologic dream was realized: Most amyloid plaques – the primary pathologic marker for AD – were eliminated from the brains of patients with late pre-AD or early AD.

Implications for the amyloid hypothesis

The reduction of amyloid plaques has been argued by many scientists and clinical authorities to be the likely pharmacologic solution for AD. These trials are appropriately viewed as a test of the hypothesis that amyloid bodies are a primary cause of the neurobehavioral symptoms we call AD.

In parallel with that striking reduction in amyloid bodies, drug-treated patients had an initially slower progression of neurobehavioral decline than did placebo-treated control patients. That slowing in symptom progression was accompanied by a modest but statistically significant difference in neurobehavioral ability. After several months in treatment, the rate of decline again paralleled that recorded in the control group. The sustained difference of about a half point on cognitive assessment scores separating treatment and control participants was well short of the 1.5-point difference typically considered clinically significant.

A small number of unexpected and unexplained deaths occurred in the treatment groups. Brain swelling and/or micro-hemorrhages were seen in 20%-30% of treated individuals. Significant brain shrinkage was recorded. These adverse findings are indicative of drug-induced trauma in the target organ for these drugs (i.e., the brain) and were the basis for a boxed warning label for drug usage. Antiamyloid drug treatment was not effective in patients who had higher initial numbers of amyloid plaques, indicating that these drugs would not measurably help the majority of AD patients, who are at more advanced disease stages.

These drugs do not appear to be an “answer” for AD. A modest delay in progression does not mean that we’re on a path to a “cure.” Treatment cost estimates are high – more than $80,000 per year. With requisite PET exams and high copays, patient accessibility issues will be daunting.

Of note, in my view, the trials of these drugs do not support the hypothesis that amyloid is the primary neuropathologic agent underlying the progressive neurobehavioral decline in AD. To the contrary, they add strong support for the counterargument that the emergence of amyloid plaques is an effect and not a fundamental cause of that progressive loss of neurologic function that we ultimately define as “Alzheimer’s disease.”
 

Time to switch gears

The more obvious path to winning the battle against this human scourge is prevention. A recent analysis published in The Lancet argued that about 40% of AD and other dementias are potentially preventable. I disagree. I believe that 80%-90% of prospective cases can be substantially delayed or prevented. Studies have shown that progression to AD or other dementias is driven primarily by the progressive deterioration of organic brain health, expressed by the loss of what psychologists have termed “cognitive reserve.” Cognitive reserve is resilience arising from active brain usage, akin to physical resilience attributable to a physically active life. Scientific studies have shown us that an individual’s cognitive resilience (reserve) is a greater predictor of risk for dementia than are amyloid plaques – indeed, greater than any combination of pathologic markers in dementia patients.

Building up cognitive reserve

It’s increasingly clear to this observer that cognitive reserve is synonymous with organic brain health. The primary factors that underlie cognitive reserve are processing speed in the brain, executive control, response withholding, memory acquisition, reasoning, and attention abilities. Faster, more accurate brains are necessarily more physically optimized. They necessarily sustain brain system connectivity. They are necessarily healthier. Such brains bear a relatively low risk of developing AD or other dementias, just as physically healthier bodies bear a lower risk of being prematurely banished to semi-permanent residence in an easy chair or a bed.

Brain health can be sustained by deploying inexpensive, self-administered, app-based assessments of neurologic performance limits, which inform patients and their medical teams about general brain health status. These assessments can help doctors guide their patients to adopt more intelligent brain-healthy lifestyles, or direct them to the “brain gym” to progressively exercise their brains in ways that contribute to rapid, potentially large-scale, rejuvenating improvements in physical and functional brain health.

Randomized controlled trials incorporating different combinations of physical exercise, diet, and cognitive training have recorded significant improvements in physical and functional neurologic status, indicating substantially advanced brain health. Consistent moderate-to-intense physical exercise, brain- and heart-healthy eating habits, and, particularly, computerized brain training have repeatedly been shown to improve cognitive function and physically rejuvenate the brain. With cognitive training in the right forms, improvements in processing speed and other measures manifest improving brain health and greater safety.

In the National Institutes of Health–funded ACTIVE study with more than 2,800 older adults, just 10-18 hours of a specific speed of processing training (now part of BrainHQ, a program that I was involved in developing) reduced the probability of a progression to dementia over the following 10 years by 29%, and by 48% in those who did the most training.

This approach is several orders of magnitude less expensive than the pricey new AD drugs. It presents less serious issues of accessibility and has no side effects. It delivers far more powerful therapeutic benefits in older normal and at-risk populations.

Sustained wellness supporting prevention is the far more sensible medical way forward to save people from AD and other dementias – at a far lower medical and societal cost.

Dr. Merzenich is professor emeritus, department of neuroscience, University of California, San Francisco. He reported conflicts of interest with Posit Science, Stronger Brains, and the National Institutes of Health.

A version of this article first appeared on Medscape.com.

TOPLINE:

Loneliness is associated with a higher risk of developing Parkinson’s disease (PD) across demographic groups and independent of other risk factors, data from nearly 500,000 U.K. adults suggest.

METHODOLOGY:

• Loneliness is associated with illness and death, including higher risk of neurodegenerative diseases, but no study has examined whether the association between loneliness and detrimental outcomes extends to PD.
• The current analysis included 491,603 U.K. Biobank participants (mean age, 56; 54% women) without a diagnosis of PD at baseline.
• Loneliness was assessed by a single question at baseline and incident PD was ascertained via health records over 15 years.
• Researchers assessed whether the association between loneliness and PD was moderated by age, sex, or genetic risk and whether the association was accounted for by sociodemographic factors; behavioral, mental, physical, or social factors; or genetic risk.

TAKEAWAY:

• Roughly 19% of the cohort reported being lonely. Compared with those who were not lonely, those who did report being lonely were slightly younger and were more likely to be women. They also had fewer resources, more health risk behaviors (current smoker and physically inactive), and worse physical and mental health.
• Over 15+ years of follow-up, 2,822 participants developed PD (incidence rate: 47 per 100,000 person-years). Compared with those who did not develop PD, those who did were older and more likely to be male, former smokers, have higher BMI and PD polygenetic risk score, and to have diabetes, hypertension, myocardial infarction or stroke, anxiety, or depression.
• In the primary analysis, individuals who reported being lonely had a higher risk for PD (hazard ratio, 1.37) – an association that remained after accounting for demographic and socioeconomic status, social isolation, PD polygenetic risk score, smoking, physical activity, BMI, diabetes, hypertension, stroke, myocardial infarction, depression, and having ever seen a psychiatrist (fully adjusted HR, 1.25). 
• The association between loneliness and incident PD was not moderated by sex, age, or polygenetic risk score.
• Contrary to expectations for a prodromal syndrome, loneliness was not associated with incident PD in the first 5 years after baseline but was associated with PD risk in the subsequent 10 years of follow-up (HR, 1.32).

IN PRACTICE:

“Our findings complement other evidence that loneliness is a psychosocial determinant of health associated with increased risk of morbidity and mortality [and] supports recent calls for the protective and healing effects of personally meaningful social connection,” the authors write.

SOURCE:

The study, with first author Antonio Terracciano, PhD, of Florida State University College of Medicine, Tallahassee, was published online  in JAMA Neurology.

LIMITATIONS:

This observational study could not determine causality or whether reverse causality could explain the association. Loneliness was assessed by a single yes/no question. PD diagnosis relied on hospital admission and death records and may have missed early PD diagnoses.

DISCLOSURES:

Funding for the study was provided by the National Institutes of Health and National Institute on Aging. The authors report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

TOPLINE:

Loneliness is associated with a higher risk of developing Parkinson’s disease (PD) across demographic groups and independent of other risk factors, data from nearly 500,000 U.K. adults suggest.

METHODOLOGY:

• Loneliness is associated with illness and death, including higher risk of neurodegenerative diseases, but no study has examined whether the association between loneliness and detrimental outcomes extends to PD.
• The current analysis included 491,603 U.K. Biobank participants (mean age, 56; 54% women) without a diagnosis of PD at baseline.
• Loneliness was assessed by a single question at baseline and incident PD was ascertained via health records over 15 years.
• Researchers assessed whether the association between loneliness and PD was moderated by age, sex, or genetic risk and whether the association was accounted for by sociodemographic factors; behavioral, mental, physical, or social factors; or genetic risk.

TAKEAWAY:

• Roughly 19% of the cohort reported being lonely. Compared with those who were not lonely, those who did report being lonely were slightly younger and were more likely to be women. They also had fewer resources, more health risk behaviors (current smoker and physically inactive), and worse physical and mental health.
• Over 15+ years of follow-up, 2,822 participants developed PD (incidence rate: 47 per 100,000 person-years). Compared with those who did not develop PD, those who did were older and more likely to be male, former smokers, have higher BMI and PD polygenetic risk score, and to have diabetes, hypertension, myocardial infarction or stroke, anxiety, or depression.
• In the primary analysis, individuals who reported being lonely had a higher risk for PD (hazard ratio, 1.37) – an association that remained after accounting for demographic and socioeconomic status, social isolation, PD polygenetic risk score, smoking, physical activity, BMI, diabetes, hypertension, stroke, myocardial infarction, depression, and having ever seen a psychiatrist (fully adjusted HR, 1.25). 
• The association between loneliness and incident PD was not moderated by sex, age, or polygenetic risk score.
• Contrary to expectations for a prodromal syndrome, loneliness was not associated with incident PD in the first 5 years after baseline but was associated with PD risk in the subsequent 10 years of follow-up (HR, 1.32).

IN PRACTICE:

“Our findings complement other evidence that loneliness is a psychosocial determinant of health associated with increased risk of morbidity and mortality [and] supports recent calls for the protective and healing effects of personally meaningful social connection,” the authors write.

SOURCE:

The study, with first author Antonio Terracciano, PhD, of Florida State University College of Medicine, Tallahassee, was published online  in JAMA Neurology.

LIMITATIONS:

This observational study could not determine causality or whether reverse causality could explain the association. Loneliness was assessed by a single yes/no question. PD diagnosis relied on hospital admission and death records and may have missed early PD diagnoses.

DISCLOSURES:

Funding for the study was provided by the National Institutes of Health and National Institute on Aging. The authors report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

TOPLINE:

Loneliness is associated with a higher risk of developing Parkinson’s disease (PD) across demographic groups and independent of other risk factors, data from nearly 500,000 U.K. adults suggest.

METHODOLOGY:

• Loneliness is associated with illness and death, including higher risk of neurodegenerative diseases, but no study has examined whether the association between loneliness and detrimental outcomes extends to PD.
• The current analysis included 491,603 U.K. Biobank participants (mean age, 56; 54% women) without a diagnosis of PD at baseline.
• Loneliness was assessed by a single question at baseline and incident PD was ascertained via health records over 15 years.
• Researchers assessed whether the association between loneliness and PD was moderated by age, sex, or genetic risk and whether the association was accounted for by sociodemographic factors; behavioral, mental, physical, or social factors; or genetic risk.

TAKEAWAY:

• Roughly 19% of the cohort reported being lonely. Compared with those who were not lonely, those who did report being lonely were slightly younger and were more likely to be women. They also had fewer resources, more health risk behaviors (current smoker and physically inactive), and worse physical and mental health.
• Over 15+ years of follow-up, 2,822 participants developed PD (incidence rate: 47 per 100,000 person-years). Compared with those who did not develop PD, those who did were older and more likely to be male, former smokers, have higher BMI and PD polygenetic risk score, and to have diabetes, hypertension, myocardial infarction or stroke, anxiety, or depression.
• In the primary analysis, individuals who reported being lonely had a higher risk for PD (hazard ratio, 1.37) – an association that remained after accounting for demographic and socioeconomic status, social isolation, PD polygenetic risk score, smoking, physical activity, BMI, diabetes, hypertension, stroke, myocardial infarction, depression, and having ever seen a psychiatrist (fully adjusted HR, 1.25). 
• The association between loneliness and incident PD was not moderated by sex, age, or polygenetic risk score.
• Contrary to expectations for a prodromal syndrome, loneliness was not associated with incident PD in the first 5 years after baseline but was associated with PD risk in the subsequent 10 years of follow-up (HR, 1.32).

IN PRACTICE:

“Our findings complement other evidence that loneliness is a psychosocial determinant of health associated with increased risk of morbidity and mortality [and] supports recent calls for the protective and healing effects of personally meaningful social connection,” the authors write.

SOURCE:

The study, with first author Antonio Terracciano, PhD, of Florida State University College of Medicine, Tallahassee, was published online  in JAMA Neurology.

LIMITATIONS:

This observational study could not determine causality or whether reverse causality could explain the association. Loneliness was assessed by a single yes/no question. PD diagnosis relied on hospital admission and death records and may have missed early PD diagnoses.

DISCLOSURES:

Funding for the study was provided by the National Institutes of Health and National Institute on Aging. The authors report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

I have written before about the COSMOS study and its finding that multivitamins (and chocolate) did not improve brain or cardiovascular health. So I was surprised to read that a “new” study found that vitamins can forestall dementia and age-related cognitive decline.

Upon closer look, the new data are neither new nor convincing, at least to me.

©Graça Victoria/iStockphoto.com

Chocolate and multivitamins for CVD and cancer prevention

The large randomized COSMOS trial was supposed to be the definitive study on chocolate that would establish its heart-health benefits without a doubt. Or, rather, the benefits of a cocoa bean extract in pill form given to healthy, older volunteers. The COSMOS study was negative. Chocolate, or the cocoa bean extract they used, did not reduce cardiovascular events.

And yet for all the prepublication importance attached to COSMOS, it is scarcely mentioned. Had it been positive, rest assured that Mars, the candy bar company that cofunded the research, and other interested parties would have been shouting it from the rooftops. As it is, they’re already spinning it.

Which brings us to the multivitamin component. COSMOS actually had a 2 × 2 design. In other words, there were four groups in this study: chocolate plus multivitamin, chocolate plus placebo, placebo plus multivitamin, and placebo plus placebo. This type of study design allows you to study two different interventions simultaneously, provided that they are independent and do not interact with each other. In addition to the primary cardiovascular endpoint, they also studied a cancer endpoint.

The multivitamin supplement didn’t reduce cardiovascular events either. Nor did it affect cancer outcomes. The main COSMOS study was negative and reinforced what countless other studies have proven: Taking a daily multivitamin does not reduce your risk of having a heart attack or developing cancer.
 

But wait, there’s more: COSMOS-Mind

But no researcher worth his salt studies just one or two endpoints in a study. The participants also underwent neurologic and memory testing. These results were reported separately in the COSMOS-Mind study.

COSMOS-Mind is often described as a separate (or “new”) study. In reality, it included the same participants from the original COSMOS trial and measured yet another primary outcome of cognitive performance on a series of tests administered by telephone. Although there is nothing inherently wrong with studying multiple outcomes in your patient population (after all, that salami isn’t going to slice itself), they cannot all be primary outcomes. Some, by necessity, must be secondary hypothesis–generating outcomes. If you test enough endpoints, multiple hypothesis testing dictates that eventually you will get a positive result simply by chance.

There was a time when the neurocognitive outcomes of COSMOS would have been reported in the same paper as the cardiovascular outcomes, but that time seems to have passed us by. Researchers live or die by the number of their publications, and there is an inherent advantage to squeezing as many publications as possible from the same dataset. Though, to be fair, the journal would probably have asked them to split up the paper as well.

In brief, the cocoa extract again fell short in COSMOS-Mind, but the multivitamin arm did better on the composite cognitive outcome. It was a fairly small difference – a 0.07-point improvement on the z-score at the 3-year mark (the z-score is the mean divided by the standard deviation). Much was also made of the fact that the improvement seemed to vary by prior history of cardiovascular disease (CVD). Those with a history of CVD had a 0.11-point improvement, whereas those without had a 0.06-point improvement. The authors couldn’t offer a definitive explanation for these findings. Any argument that multivitamins improve cardiovascular health and therefore prevent vascular dementia has to contend with the fact that the main COSMOS study didn’t show a cardiovascular benefit for vitamins. Speculation that you are treating nutritional deficiencies is exactly that: speculation.

A more salient question is: What does a 0.07-point improvement on the z-score mean clinically? This study didn’t assess whether a multivitamin supplement prevented dementia or allowed people to live independently for longer. In fairness, that would have been exceptionally difficult to do and would have required a much longer study.

Their one attempt to quantify the cognitive benefit clinically was a calculation about normal age-related decline. Test scores were 0.045 points lower for every 1-year increase in age among participants (their mean age was 73 years). So the authors contend that a 0.07-point increase, or the 0.083-point increase that they found at year 3, corresponds to 1.8 years of age-related decline forestalled. Whether this is an appropriate assumption, I leave for the reader to decide.
 

COSMOS-Web and replication

The results of COSMOS-Mind were seemingly bolstered by the recent publication of COSMOS-Web. Although I’ve seen this study described as having replicated the results of COSMOS-Mind, that description is a bit misleading. This was yet another ancillary COSMOS study; more than half of the 2,262 participants in COSMOS-Mind were also included in COSMOS-Web. Replicating results in the same people isn’t true replication.

The main difference between COSMOS-Mind and COSMOS-Web is that the former used a telephone interview to administer the cognitive tests and the latter used the Internet. They also had different endpoints, with COSMOS-Web looking at immediate recall rather than a global test composite.

COSMOS-Web was a positive study in that patients getting the multivitamin supplement did better on the test for immediate memory recall (remembering a list of 20 words), though they didn’t improve on tests of memory retention, executive function, or novel object recognition (basically a test where subjects have to identify matching geometric patterns and then recall them later). They were able to remember an additional 0.71 word on average, compared with 0.44 word in the placebo group. (For the record, it found no benefit for the cocoa extract).

Everybody does better on memory tests the second time around because practice makes perfect, hence the improvement in the placebo group. This benefit at 1 year did not survive to the end of follow-up at 3 years, in contrast to COSMOS-Mind, where the benefit was not apparent at 1 year and seen only at year 3. A history of cardiovascular disease didn’t seem to affect the results in COSMOS-Web as it did in COSMOS-Mind. As far as replications go, COSMOS-Web has some very non-negligible differences, compared with COSMOS-Mind. This incongruity, especially given the overlap in the patient populations is hard to reconcile. If COSMOS-Web was supposed to assuage any doubts that persisted after COSMOS-Mind, it hasn’t for me.
 

One of these studies is not like the others

Finally, although the COSMOS trial and all its ancillary study analyses suggest a neurocognitive benefit to multivitamin supplementation, it’s not the first study to test the matter. The Age-Related Eye Disease Study looked at vitamin C, vitamin E, beta-carotene, zinc, and copper. There was no benefit on any of the six cognitive tests administered to patients. The Women’s Health Study, the Women’s Antioxidant Cardiovascular Study and PREADViSE have all failed to show any benefit to the various vitamins and minerals they studied. A meta-analysis of 11 trials found no benefit to B vitamins in slowing cognitive aging.

The claim that COSMOS is the “first” study to test the hypothesis hinges on some careful wordplay. Prior studies tested specific vitamins, not a multivitamin. In the discussion of the paper, these other studies are critiqued for being short term. But the Physicians’ Health Study II did in fact study a multivitamin and assessed cognitive performance on average 2.5 years after randomization. It found no benefit. The authors of COSMOS-Web critiqued the 2.5-year wait to perform cognitive testing, saying it would have missed any short-term benefits. Although, given that they simultaneously praised their 3 years of follow-up, the criticism is hard to fully accept or even understand.

Whether follow-up is short or long, uses individual vitamins or a multivitamin, the results excluding COSMOS are uniformly negative. I for one am skeptical that a multivitamin or any individual vitamin can prevent dementia. Same goes for chocolate.

Do enough tests in the same population, and something will rise above the noise just by chance. When you get a positive result in your research, it’s always exciting. But when a slew of studies that came before you are negative, you aren’t groundbreaking. You’re an outlier.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal. He has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.

I have written before about the COSMOS study and its finding that multivitamins (and chocolate) did not improve brain or cardiovascular health. So I was surprised to read that a “new” study found that vitamins can forestall dementia and age-related cognitive decline.

Upon closer look, the new data are neither new nor convincing, at least to me.

©Graça Victoria/iStockphoto.com

Chocolate and multivitamins for CVD and cancer prevention

The large randomized COSMOS trial was supposed to be the definitive study on chocolate that would establish its heart-health benefits without a doubt. Or, rather, the benefits of a cocoa bean extract in pill form given to healthy, older volunteers. The COSMOS study was negative. Chocolate, or the cocoa bean extract they used, did not reduce cardiovascular events.

And yet for all the prepublication importance attached to COSMOS, it is scarcely mentioned. Had it been positive, rest assured that Mars, the candy bar company that cofunded the research, and other interested parties would have been shouting it from the rooftops. As it is, they’re already spinning it.

Which brings us to the multivitamin component. COSMOS actually had a 2 × 2 design. In other words, there were four groups in this study: chocolate plus multivitamin, chocolate plus placebo, placebo plus multivitamin, and placebo plus placebo. This type of study design allows you to study two different interventions simultaneously, provided that they are independent and do not interact with each other. In addition to the primary cardiovascular endpoint, they also studied a cancer endpoint.

The multivitamin supplement didn’t reduce cardiovascular events either. Nor did it affect cancer outcomes. The main COSMOS study was negative and reinforced what countless other studies have proven: Taking a daily multivitamin does not reduce your risk of having a heart attack or developing cancer.
 

But wait, there’s more: COSMOS-Mind

But no researcher worth his salt studies just one or two endpoints in a study. The participants also underwent neurologic and memory testing. These results were reported separately in the COSMOS-Mind study.

COSMOS-Mind is often described as a separate (or “new”) study. In reality, it included the same participants from the original COSMOS trial and measured yet another primary outcome of cognitive performance on a series of tests administered by telephone. Although there is nothing inherently wrong with studying multiple outcomes in your patient population (after all, that salami isn’t going to slice itself), they cannot all be primary outcomes. Some, by necessity, must be secondary hypothesis–generating outcomes. If you test enough endpoints, multiple hypothesis testing dictates that eventually you will get a positive result simply by chance.

There was a time when the neurocognitive outcomes of COSMOS would have been reported in the same paper as the cardiovascular outcomes, but that time seems to have passed us by. Researchers live or die by the number of their publications, and there is an inherent advantage to squeezing as many publications as possible from the same dataset. Though, to be fair, the journal would probably have asked them to split up the paper as well.

In brief, the cocoa extract again fell short in COSMOS-Mind, but the multivitamin arm did better on the composite cognitive outcome. It was a fairly small difference – a 0.07-point improvement on the z-score at the 3-year mark (the z-score is the mean divided by the standard deviation). Much was also made of the fact that the improvement seemed to vary by prior history of cardiovascular disease (CVD). Those with a history of CVD had a 0.11-point improvement, whereas those without had a 0.06-point improvement. The authors couldn’t offer a definitive explanation for these findings. Any argument that multivitamins improve cardiovascular health and therefore prevent vascular dementia has to contend with the fact that the main COSMOS study didn’t show a cardiovascular benefit for vitamins. Speculation that you are treating nutritional deficiencies is exactly that: speculation.

A more salient question is: What does a 0.07-point improvement on the z-score mean clinically? This study didn’t assess whether a multivitamin supplement prevented dementia or allowed people to live independently for longer. In fairness, that would have been exceptionally difficult to do and would have required a much longer study.

Their one attempt to quantify the cognitive benefit clinically was a calculation about normal age-related decline. Test scores were 0.045 points lower for every 1-year increase in age among participants (their mean age was 73 years). So the authors contend that a 0.07-point increase, or the 0.083-point increase that they found at year 3, corresponds to 1.8 years of age-related decline forestalled. Whether this is an appropriate assumption, I leave for the reader to decide.
 

COSMOS-Web and replication

The results of COSMOS-Mind were seemingly bolstered by the recent publication of COSMOS-Web. Although I’ve seen this study described as having replicated the results of COSMOS-Mind, that description is a bit misleading. This was yet another ancillary COSMOS study; more than half of the 2,262 participants in COSMOS-Mind were also included in COSMOS-Web. Replicating results in the same people isn’t true replication.

The main difference between COSMOS-Mind and COSMOS-Web is that the former used a telephone interview to administer the cognitive tests and the latter used the Internet. They also had different endpoints, with COSMOS-Web looking at immediate recall rather than a global test composite.

COSMOS-Web was a positive study in that patients getting the multivitamin supplement did better on the test for immediate memory recall (remembering a list of 20 words), though they didn’t improve on tests of memory retention, executive function, or novel object recognition (basically a test where subjects have to identify matching geometric patterns and then recall them later). They were able to remember an additional 0.71 word on average, compared with 0.44 word in the placebo group. (For the record, it found no benefit for the cocoa extract).

Everybody does better on memory tests the second time around because practice makes perfect, hence the improvement in the placebo group. This benefit at 1 year did not survive to the end of follow-up at 3 years, in contrast to COSMOS-Mind, where the benefit was not apparent at 1 year and seen only at year 3. A history of cardiovascular disease didn’t seem to affect the results in COSMOS-Web as it did in COSMOS-Mind. As far as replications go, COSMOS-Web has some very non-negligible differences, compared with COSMOS-Mind. This incongruity, especially given the overlap in the patient populations is hard to reconcile. If COSMOS-Web was supposed to assuage any doubts that persisted after COSMOS-Mind, it hasn’t for me.
 

One of these studies is not like the others

Finally, although the COSMOS trial and all its ancillary study analyses suggest a neurocognitive benefit to multivitamin supplementation, it’s not the first study to test the matter. The Age-Related Eye Disease Study looked at vitamin C, vitamin E, beta-carotene, zinc, and copper. There was no benefit on any of the six cognitive tests administered to patients. The Women’s Health Study, the Women’s Antioxidant Cardiovascular Study and PREADViSE have all failed to show any benefit to the various vitamins and minerals they studied. A meta-analysis of 11 trials found no benefit to B vitamins in slowing cognitive aging.

The claim that COSMOS is the “first” study to test the hypothesis hinges on some careful wordplay. Prior studies tested specific vitamins, not a multivitamin. In the discussion of the paper, these other studies are critiqued for being short term. But the Physicians’ Health Study II did in fact study a multivitamin and assessed cognitive performance on average 2.5 years after randomization. It found no benefit. The authors of COSMOS-Web critiqued the 2.5-year wait to perform cognitive testing, saying it would have missed any short-term benefits. Although, given that they simultaneously praised their 3 years of follow-up, the criticism is hard to fully accept or even understand.

Whether follow-up is short or long, uses individual vitamins or a multivitamin, the results excluding COSMOS are uniformly negative. I for one am skeptical that a multivitamin or any individual vitamin can prevent dementia. Same goes for chocolate.

Do enough tests in the same population, and something will rise above the noise just by chance. When you get a positive result in your research, it’s always exciting. But when a slew of studies that came before you are negative, you aren’t groundbreaking. You’re an outlier.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal. He has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.

I have written before about the COSMOS study and its finding that multivitamins (and chocolate) did not improve brain or cardiovascular health. So I was surprised to read that a “new” study found that vitamins can forestall dementia and age-related cognitive decline.

Upon closer look, the new data are neither new nor convincing, at least to me.

©Graça Victoria/iStockphoto.com

Chocolate and multivitamins for CVD and cancer prevention

The large randomized COSMOS trial was supposed to be the definitive study on chocolate that would establish its heart-health benefits without a doubt. Or, rather, the benefits of a cocoa bean extract in pill form given to healthy, older volunteers. The COSMOS study was negative. Chocolate, or the cocoa bean extract they used, did not reduce cardiovascular events.

And yet for all the prepublication importance attached to COSMOS, it is scarcely mentioned. Had it been positive, rest assured that Mars, the candy bar company that cofunded the research, and other interested parties would have been shouting it from the rooftops. As it is, they’re already spinning it.

Which brings us to the multivitamin component. COSMOS actually had a 2 × 2 design. In other words, there were four groups in this study: chocolate plus multivitamin, chocolate plus placebo, placebo plus multivitamin, and placebo plus placebo. This type of study design allows you to study two different interventions simultaneously, provided that they are independent and do not interact with each other. In addition to the primary cardiovascular endpoint, they also studied a cancer endpoint.

The multivitamin supplement didn’t reduce cardiovascular events either. Nor did it affect cancer outcomes. The main COSMOS study was negative and reinforced what countless other studies have proven: Taking a daily multivitamin does not reduce your risk of having a heart attack or developing cancer.
 

But wait, there’s more: COSMOS-Mind

But no researcher worth his salt studies just one or two endpoints in a study. The participants also underwent neurologic and memory testing. These results were reported separately in the COSMOS-Mind study.

COSMOS-Mind is often described as a separate (or “new”) study. In reality, it included the same participants from the original COSMOS trial and measured yet another primary outcome of cognitive performance on a series of tests administered by telephone. Although there is nothing inherently wrong with studying multiple outcomes in your patient population (after all, that salami isn’t going to slice itself), they cannot all be primary outcomes. Some, by necessity, must be secondary hypothesis–generating outcomes. If you test enough endpoints, multiple hypothesis testing dictates that eventually you will get a positive result simply by chance.

There was a time when the neurocognitive outcomes of COSMOS would have been reported in the same paper as the cardiovascular outcomes, but that time seems to have passed us by. Researchers live or die by the number of their publications, and there is an inherent advantage to squeezing as many publications as possible from the same dataset. Though, to be fair, the journal would probably have asked them to split up the paper as well.

In brief, the cocoa extract again fell short in COSMOS-Mind, but the multivitamin arm did better on the composite cognitive outcome. It was a fairly small difference – a 0.07-point improvement on the z-score at the 3-year mark (the z-score is the mean divided by the standard deviation). Much was also made of the fact that the improvement seemed to vary by prior history of cardiovascular disease (CVD). Those with a history of CVD had a 0.11-point improvement, whereas those without had a 0.06-point improvement. The authors couldn’t offer a definitive explanation for these findings. Any argument that multivitamins improve cardiovascular health and therefore prevent vascular dementia has to contend with the fact that the main COSMOS study didn’t show a cardiovascular benefit for vitamins. Speculation that you are treating nutritional deficiencies is exactly that: speculation.

A more salient question is: What does a 0.07-point improvement on the z-score mean clinically? This study didn’t assess whether a multivitamin supplement prevented dementia or allowed people to live independently for longer. In fairness, that would have been exceptionally difficult to do and would have required a much longer study.

Their one attempt to quantify the cognitive benefit clinically was a calculation about normal age-related decline. Test scores were 0.045 points lower for every 1-year increase in age among participants (their mean age was 73 years). So the authors contend that a 0.07-point increase, or the 0.083-point increase that they found at year 3, corresponds to 1.8 years of age-related decline forestalled. Whether this is an appropriate assumption, I leave for the reader to decide.
 

COSMOS-Web and replication

The results of COSMOS-Mind were seemingly bolstered by the recent publication of COSMOS-Web. Although I’ve seen this study described as having replicated the results of COSMOS-Mind, that description is a bit misleading. This was yet another ancillary COSMOS study; more than half of the 2,262 participants in COSMOS-Mind were also included in COSMOS-Web. Replicating results in the same people isn’t true replication.

The main difference between COSMOS-Mind and COSMOS-Web is that the former used a telephone interview to administer the cognitive tests and the latter used the Internet. They also had different endpoints, with COSMOS-Web looking at immediate recall rather than a global test composite.

COSMOS-Web was a positive study in that patients getting the multivitamin supplement did better on the test for immediate memory recall (remembering a list of 20 words), though they didn’t improve on tests of memory retention, executive function, or novel object recognition (basically a test where subjects have to identify matching geometric patterns and then recall them later). They were able to remember an additional 0.71 word on average, compared with 0.44 word in the placebo group. (For the record, it found no benefit for the cocoa extract).

Everybody does better on memory tests the second time around because practice makes perfect, hence the improvement in the placebo group. This benefit at 1 year did not survive to the end of follow-up at 3 years, in contrast to COSMOS-Mind, where the benefit was not apparent at 1 year and seen only at year 3. A history of cardiovascular disease didn’t seem to affect the results in COSMOS-Web as it did in COSMOS-Mind. As far as replications go, COSMOS-Web has some very non-negligible differences, compared with COSMOS-Mind. This incongruity, especially given the overlap in the patient populations is hard to reconcile. If COSMOS-Web was supposed to assuage any doubts that persisted after COSMOS-Mind, it hasn’t for me.
 

One of these studies is not like the others

Finally, although the COSMOS trial and all its ancillary study analyses suggest a neurocognitive benefit to multivitamin supplementation, it’s not the first study to test the matter. The Age-Related Eye Disease Study looked at vitamin C, vitamin E, beta-carotene, zinc, and copper. There was no benefit on any of the six cognitive tests administered to patients. The Women’s Health Study, the Women’s Antioxidant Cardiovascular Study and PREADViSE have all failed to show any benefit to the various vitamins and minerals they studied. A meta-analysis of 11 trials found no benefit to B vitamins in slowing cognitive aging.

The claim that COSMOS is the “first” study to test the hypothesis hinges on some careful wordplay. Prior studies tested specific vitamins, not a multivitamin. In the discussion of the paper, these other studies are critiqued for being short term. But the Physicians’ Health Study II did in fact study a multivitamin and assessed cognitive performance on average 2.5 years after randomization. It found no benefit. The authors of COSMOS-Web critiqued the 2.5-year wait to perform cognitive testing, saying it would have missed any short-term benefits. Although, given that they simultaneously praised their 3 years of follow-up, the criticism is hard to fully accept or even understand.

Whether follow-up is short or long, uses individual vitamins or a multivitamin, the results excluding COSMOS are uniformly negative. I for one am skeptical that a multivitamin or any individual vitamin can prevent dementia. Same goes for chocolate.

Do enough tests in the same population, and something will rise above the noise just by chance. When you get a positive result in your research, it’s always exciting. But when a slew of studies that came before you are negative, you aren’t groundbreaking. You’re an outlier.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal. He has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.

Given the patient's insidious cognitive decline, as well as increased agitation, irritability, anxiety, social isolation, inability to fully manage finances, loss of routine hygienic practices, and loss of interest in regular meals, this patient is diagnosed with probable Alzheimer's disease (AD) dementia and is referred to a specialist for further testing.

AD is one of the most common forms of dementia. More than 6 million people in the United States have clinical AD or mild cognitive impairment because of AD. By 2060, the incidence of AD is expected to grow to 15 million people. AD is classified into four stages: preclinical, mild, moderate, and severe. Patients with preclinical AD — a relatively new classification currently only used for research — do not yet show abnormal results on physical exam or mental status testing, but areas of the brain are undergoing pathologic changes. Mild AD signs and symptoms include memory loss, compromised judgment, trouble handling money and paying bills, mood and personality changes, and increased anxiety. People with moderate AD show increasing signs of memory loss and confusion, problems with recognizing family and friends, and difficulty with organizing thoughts and thinking logically, and they repeat themselves in conversation, among other symptoms. Severe AD is generally described as a complete loss of self, with the inability to recognize family and friends, inability to communicate effectively, and complete dependence on others for care. 

Diagnosing AD currently relies on a clinical approach. A complete physical examination, with a detailed neurologic examination and a mental status examination, is used to evaluate disease stage and rule out comorbid conditions. Initial mental status testing should evaluate attention and concentration, recent and remote memory, language, praxis, executive function, and visuospatial function. Imaging studies may be performed to rule out other treatable causes of cognitive decline. In addition, volumetric studies of the hippocampus and 2-[¹⁸F]fluoro-2-deoxy-D-glucose PET with or without amyloid imaging can be used for early detection and differentiating dementia etiologies. Lumbar puncture as a diagnostic measure for levels of tau (which is often elevated in AD) and amyloid (which is often reduced in AD) is currently reserved for research settings.

Although the cause of AD is unknown, experts believe that environmental and genetic risk factors trigger a pathophysiologic cascade that, over decades, leads to Alzheimer's pathology and dementia. Universally accepted pathologic hallmarks of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs). NFTs result from changes in the tau protein, a key chemical in neuronal support structures, and are associated with malfunctions in communication between neurons as well as cell death. Beta-amyloid plaques are dense, mostly insoluble deposits that develop around neurons in the hippocampus and other regions in the cerebral cortex used for decision-making, disrupting function and leading to brain atrophy. Risk factors for AD include advancing age, family history, APOE e4 genotype, insulin resistance, hypertension, depression, and traumatic brain injury.

After an AD diagnosis, physicians should encourage the involvement of family and friends who agree to become more involved in the patient's care as the disease progresses. These individuals need to understand the patient's wishes around care, especially for the future, when the patient is no longer able to make decisions. The patient may also consider establishing medical advance directives and durable power of attorney for medical and financial decision-making. Caregivers supporting the patient are encouraged to help balance the physical needs of the patient while maintaining respect for them as a competent adult to the extent allowed by the progression of their disease. 

Currently, AD treatments are focused on symptomatic therapies that modulate neurotransmitters — either acetylcholine or glutamate. The standard medical treatment includes cholinesterase inhibitors and a partial N-methyl-D-aspartate antagonist. Two amyloid-directed antibodies (aducanumab, lecanemab) are currently available in the US for individuals with AD exhibiting mild cognitive impairment or mild dementia. A third agent currently in clinical trials (donanemab) has shown significantly slowed clinical progression after 1.5 years among clinical trial participants with early symptomatic AD and amyloid and tau pathology.

Jasvinder Chawla, MD, Professor of Neurology, Loyola University Medical Center, Maywood; Director, Clinical Neurophysiology Lab, Department of Neurology, Hines VA Hospital, Hines, IL.

Jasvinder Chawla, MD, has disclosed no relevant financial relationships.

Image Quizzes are fictional or fictionalized clinical scenarios intended to provide evidence-based educational takeaways.

Given the patient's insidious cognitive decline, as well as increased agitation, irritability, anxiety, social isolation, inability to fully manage finances, loss of routine hygienic practices, and loss of interest in regular meals, this patient is diagnosed with probable Alzheimer's disease (AD) dementia and is referred to a specialist for further testing.

AD is one of the most common forms of dementia. More than 6 million people in the United States have clinical AD or mild cognitive impairment because of AD. By 2060, the incidence of AD is expected to grow to 15 million people. AD is classified into four stages: preclinical, mild, moderate, and severe. Patients with preclinical AD — a relatively new classification currently only used for research — do not yet show abnormal results on physical exam or mental status testing, but areas of the brain are undergoing pathologic changes. Mild AD signs and symptoms include memory loss, compromised judgment, trouble handling money and paying bills, mood and personality changes, and increased anxiety. People with moderate AD show increasing signs of memory loss and confusion, problems with recognizing family and friends, and difficulty with organizing thoughts and thinking logically, and they repeat themselves in conversation, among other symptoms. Severe AD is generally described as a complete loss of self, with the inability to recognize family and friends, inability to communicate effectively, and complete dependence on others for care. 

Diagnosing AD currently relies on a clinical approach. A complete physical examination, with a detailed neurologic examination and a mental status examination, is used to evaluate disease stage and rule out comorbid conditions. Initial mental status testing should evaluate attention and concentration, recent and remote memory, language, praxis, executive function, and visuospatial function. Imaging studies may be performed to rule out other treatable causes of cognitive decline. In addition, volumetric studies of the hippocampus and 2-[¹⁸F]fluoro-2-deoxy-D-glucose PET with or without amyloid imaging can be used for early detection and differentiating dementia etiologies. Lumbar puncture as a diagnostic measure for levels of tau (which is often elevated in AD) and amyloid (which is often reduced in AD) is currently reserved for research settings.

Although the cause of AD is unknown, experts believe that environmental and genetic risk factors trigger a pathophysiologic cascade that, over decades, leads to Alzheimer's pathology and dementia. Universally accepted pathologic hallmarks of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs). NFTs result from changes in the tau protein, a key chemical in neuronal support structures, and are associated with malfunctions in communication between neurons as well as cell death. Beta-amyloid plaques are dense, mostly insoluble deposits that develop around neurons in the hippocampus and other regions in the cerebral cortex used for decision-making, disrupting function and leading to brain atrophy. Risk factors for AD include advancing age, family history, APOE e4 genotype, insulin resistance, hypertension, depression, and traumatic brain injury.

After an AD diagnosis, physicians should encourage the involvement of family and friends who agree to become more involved in the patient's care as the disease progresses. These individuals need to understand the patient's wishes around care, especially for the future, when the patient is no longer able to make decisions. The patient may also consider establishing medical advance directives and durable power of attorney for medical and financial decision-making. Caregivers supporting the patient are encouraged to help balance the physical needs of the patient while maintaining respect for them as a competent adult to the extent allowed by the progression of their disease. 

Currently, AD treatments are focused on symptomatic therapies that modulate neurotransmitters — either acetylcholine or glutamate. The standard medical treatment includes cholinesterase inhibitors and a partial N-methyl-D-aspartate antagonist. Two amyloid-directed antibodies (aducanumab, lecanemab) are currently available in the US for individuals with AD exhibiting mild cognitive impairment or mild dementia. A third agent currently in clinical trials (donanemab) has shown significantly slowed clinical progression after 1.5 years among clinical trial participants with early symptomatic AD and amyloid and tau pathology.

Jasvinder Chawla, MD, Professor of Neurology, Loyola University Medical Center, Maywood; Director, Clinical Neurophysiology Lab, Department of Neurology, Hines VA Hospital, Hines, IL.

Jasvinder Chawla, MD, has disclosed no relevant financial relationships.

Image Quizzes are fictional or fictionalized clinical scenarios intended to provide evidence-based educational takeaways.

Given the patient's insidious cognitive decline, as well as increased agitation, irritability, anxiety, social isolation, inability to fully manage finances, loss of routine hygienic practices, and loss of interest in regular meals, this patient is diagnosed with probable Alzheimer's disease (AD) dementia and is referred to a specialist for further testing.

AD is one of the most common forms of dementia. More than 6 million people in the United States have clinical AD or mild cognitive impairment because of AD. By 2060, the incidence of AD is expected to grow to 15 million people. AD is classified into four stages: preclinical, mild, moderate, and severe. Patients with preclinical AD — a relatively new classification currently only used for research — do not yet show abnormal results on physical exam or mental status testing, but areas of the brain are undergoing pathologic changes. Mild AD signs and symptoms include memory loss, compromised judgment, trouble handling money and paying bills, mood and personality changes, and increased anxiety. People with moderate AD show increasing signs of memory loss and confusion, problems with recognizing family and friends, and difficulty with organizing thoughts and thinking logically, and they repeat themselves in conversation, among other symptoms. Severe AD is generally described as a complete loss of self, with the inability to recognize family and friends, inability to communicate effectively, and complete dependence on others for care. 

Diagnosing AD currently relies on a clinical approach. A complete physical examination, with a detailed neurologic examination and a mental status examination, is used to evaluate disease stage and rule out comorbid conditions. Initial mental status testing should evaluate attention and concentration, recent and remote memory, language, praxis, executive function, and visuospatial function. Imaging studies may be performed to rule out other treatable causes of cognitive decline. In addition, volumetric studies of the hippocampus and 2-[¹⁸F]fluoro-2-deoxy-D-glucose PET with or without amyloid imaging can be used for early detection and differentiating dementia etiologies. Lumbar puncture as a diagnostic measure for levels of tau (which is often elevated in AD) and amyloid (which is often reduced in AD) is currently reserved for research settings.

Although the cause of AD is unknown, experts believe that environmental and genetic risk factors trigger a pathophysiologic cascade that, over decades, leads to Alzheimer's pathology and dementia. Universally accepted pathologic hallmarks of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs). NFTs result from changes in the tau protein, a key chemical in neuronal support structures, and are associated with malfunctions in communication between neurons as well as cell death. Beta-amyloid plaques are dense, mostly insoluble deposits that develop around neurons in the hippocampus and other regions in the cerebral cortex used for decision-making, disrupting function and leading to brain atrophy. Risk factors for AD include advancing age, family history, APOE e4 genotype, insulin resistance, hypertension, depression, and traumatic brain injury.

After an AD diagnosis, physicians should encourage the involvement of family and friends who agree to become more involved in the patient's care as the disease progresses. These individuals need to understand the patient's wishes around care, especially for the future, when the patient is no longer able to make decisions. The patient may also consider establishing medical advance directives and durable power of attorney for medical and financial decision-making. Caregivers supporting the patient are encouraged to help balance the physical needs of the patient while maintaining respect for them as a competent adult to the extent allowed by the progression of their disease. 

Currently, AD treatments are focused on symptomatic therapies that modulate neurotransmitters — either acetylcholine or glutamate. The standard medical treatment includes cholinesterase inhibitors and a partial N-methyl-D-aspartate antagonist. Two amyloid-directed antibodies (aducanumab, lecanemab) are currently available in the US for individuals with AD exhibiting mild cognitive impairment or mild dementia. A third agent currently in clinical trials (donanemab) has shown significantly slowed clinical progression after 1.5 years among clinical trial participants with early symptomatic AD and amyloid and tau pathology.

Jasvinder Chawla, MD, Professor of Neurology, Loyola University Medical Center, Maywood; Director, Clinical Neurophysiology Lab, Department of Neurology, Hines VA Hospital, Hines, IL.

Jasvinder Chawla, MD, has disclosed no relevant financial relationships.

Image Quizzes are fictional or fictionalized clinical scenarios intended to provide evidence-based educational takeaways.

Traumatic brain injury (TBI) that occurs in early adulthood is associated with cognitive decline in later life, results from a study of identical twins who served in World War II show.

The research, which included almost 9,000 individuals, showed that twins who had experienced a TBI were more likely to have lower cognitive function at age 70 versus their twin who did not experience a TBI, especially if they had lost consciousness or were older than age 24 at the time of injury. In addition, their cognitive decline occurred at a more rapid rate.

“We know that TBI increases the risk of developing Alzheimer’s disease and other dementias in later life, but we haven’t known about TBI’s effect on cognitive decline that does not quite meet the threshold for dementia,” study investigator Marianne Chanti-Ketterl, PhD, Duke University, Durham, N.C., said in an interview.

“We know that TBI increases the risk of dementia in later life, but we haven’t known if TBI affects cognitive function, causes cognitive decline that has not progressed to the point of severity with Alzheimer’s or dementia,” she added.

Being able to study the impact of TBI in monozygotic twins gives this study a unique strength, she noted.

“The important thing about this is that they are monozygotic twins, and we know they shared a lot of early life exposure, and almost 100% genetics,” Dr. Chanti-Ketterl said.

The study was published online in Neurology.

For the study, the investigators assessed 8,662 participants born between 1917 and 1927 who were part of the National Academy of Sciences National Research Council’s Twin Registry. The registry is composed of male veterans of World War II with a history of TBI, as reported by themselves or a caregiver.

The men were followed up for many years as part of the registry, but cognitive assessment only began in the 1990s. They were followed up at four different time points, at which time the Telephone Interview for Cognitive Status (TICS-m), an alternative to the Mini-Mental State Examination that must be given in person, was administered.

A total of 25% of participants had experienced concussion in their lifetime. Of this cohort, there were 589 pairs of monozygotic twins who were discordant (one twin had TBI and the other had not).

Among the monozygotic twin cohort, a history of any TBI and being older than age 24 at the time of TBI were associated with lower TICS-m scores.

A twin who experienced TBI after age 24 scored 0.59 points lower on the TICS-m at age 70 than his twin with no TBI, and cognitive function declined faster, by 0.05 points per year.
 

First study of its kind

Holly Elser, MD, PhD, MPH, an epidemiologist and resident physician in neurology at the University of Pennsylvania, Philadelphia, and coauthor of an accompanying editorial, said in an interview that the study’s twin design was a definite strength.

“There are lots of papers that have remarked on the apparent association between head injury and subsequent dementia or cognitive decline, but to my knowledge, this is one of the first, if not the first, to use a twin study design, which has the unique advantage of having better control over early life and genetic factors than would ever typically be possible in a dataset of unrelated adults,” said Dr. Elser.

She added that the study findings “strengthen our understanding of the relationship between TBI and later cognitive decline, so I think there is an etiologic value to the study.”

However, Dr. Elser noted that the composition of the study population may limit the extent to which the results apply to contemporary populations.

“This was a population of White male twins born between 1917 and 1927,” she noted. “However, does the experience of people who were in the military generalize to civilian populations? Are twins representative of the general population or are they unique in terms of their risk factors?”

It is always important to emphasize inclusivity in clinical research, and in dementia research in particular, Dr. Elser added.

“There are many examples of instances where racialized and otherwise economically marginalized groups have been excluded from analysis, which is problematic because there are already economically and socially marginalized groups who disproportionately bear the brunt of dementia.

“This is not a criticism of the authors’ work, that their data didn’t include a more diverse patient base, but I think it is an important reminder that we should always interpret study findings within the limitations of the data. It’s a reminder to be thoughtful about taking explicit steps to include more diverse groups in future research,” she said.

The study was funded by the National Institute on Aging/National Institutes of Health and the Department of Defense. Dr. Chanti-Ketterl and Dr. Elser have reported no relevant financial relationships.

A version of this article appeared on Medscape.com.

Traumatic brain injury (TBI) that occurs in early adulthood is associated with cognitive decline in later life, results from a study of identical twins who served in World War II show.

The research, which included almost 9,000 individuals, showed that twins who had experienced a TBI were more likely to have lower cognitive function at age 70 versus their twin who did not experience a TBI, especially if they had lost consciousness or were older than age 24 at the time of injury. In addition, their cognitive decline occurred at a more rapid rate.

“We know that TBI increases the risk of developing Alzheimer’s disease and other dementias in later life, but we haven’t known about TBI’s effect on cognitive decline that does not quite meet the threshold for dementia,” study investigator Marianne Chanti-Ketterl, PhD, Duke University, Durham, N.C., said in an interview.

“We know that TBI increases the risk of dementia in later life, but we haven’t known if TBI affects cognitive function, causes cognitive decline that has not progressed to the point of severity with Alzheimer’s or dementia,” she added.

Being able to study the impact of TBI in monozygotic twins gives this study a unique strength, she noted.

“The important thing about this is that they are monozygotic twins, and we know they shared a lot of early life exposure, and almost 100% genetics,” Dr. Chanti-Ketterl said.

The study was published online in Neurology.

For the study, the investigators assessed 8,662 participants born between 1917 and 1927 who were part of the National Academy of Sciences National Research Council’s Twin Registry. The registry is composed of male veterans of World War II with a history of TBI, as reported by themselves or a caregiver.

The men were followed up for many years as part of the registry, but cognitive assessment only began in the 1990s. They were followed up at four different time points, at which time the Telephone Interview for Cognitive Status (TICS-m), an alternative to the Mini-Mental State Examination that must be given in person, was administered.

A total of 25% of participants had experienced concussion in their lifetime. Of this cohort, there were 589 pairs of monozygotic twins who were discordant (one twin had TBI and the other had not).

Among the monozygotic twin cohort, a history of any TBI and being older than age 24 at the time of TBI were associated with lower TICS-m scores.

A twin who experienced TBI after age 24 scored 0.59 points lower on the TICS-m at age 70 than his twin with no TBI, and cognitive function declined faster, by 0.05 points per year.
 

First study of its kind

Holly Elser, MD, PhD, MPH, an epidemiologist and resident physician in neurology at the University of Pennsylvania, Philadelphia, and coauthor of an accompanying editorial, said in an interview that the study’s twin design was a definite strength.

“There are lots of papers that have remarked on the apparent association between head injury and subsequent dementia or cognitive decline, but to my knowledge, this is one of the first, if not the first, to use a twin study design, which has the unique advantage of having better control over early life and genetic factors than would ever typically be possible in a dataset of unrelated adults,” said Dr. Elser.

She added that the study findings “strengthen our understanding of the relationship between TBI and later cognitive decline, so I think there is an etiologic value to the study.”

However, Dr. Elser noted that the composition of the study population may limit the extent to which the results apply to contemporary populations.

“This was a population of White male twins born between 1917 and 1927,” she noted. “However, does the experience of people who were in the military generalize to civilian populations? Are twins representative of the general population or are they unique in terms of their risk factors?”

It is always important to emphasize inclusivity in clinical research, and in dementia research in particular, Dr. Elser added.

“There are many examples of instances where racialized and otherwise economically marginalized groups have been excluded from analysis, which is problematic because there are already economically and socially marginalized groups who disproportionately bear the brunt of dementia.

“This is not a criticism of the authors’ work, that their data didn’t include a more diverse patient base, but I think it is an important reminder that we should always interpret study findings within the limitations of the data. It’s a reminder to be thoughtful about taking explicit steps to include more diverse groups in future research,” she said.

The study was funded by the National Institute on Aging/National Institutes of Health and the Department of Defense. Dr. Chanti-Ketterl and Dr. Elser have reported no relevant financial relationships.

A version of this article appeared on Medscape.com.

Traumatic brain injury (TBI) that occurs in early adulthood is associated with cognitive decline in later life, results from a study of identical twins who served in World War II show.

The research, which included almost 9,000 individuals, showed that twins who had experienced a TBI were more likely to have lower cognitive function at age 70 versus their twin who did not experience a TBI, especially if they had lost consciousness or were older than age 24 at the time of injury. In addition, their cognitive decline occurred at a more rapid rate.

“We know that TBI increases the risk of developing Alzheimer’s disease and other dementias in later life, but we haven’t known about TBI’s effect on cognitive decline that does not quite meet the threshold for dementia,” study investigator Marianne Chanti-Ketterl, PhD, Duke University, Durham, N.C., said in an interview.

“We know that TBI increases the risk of dementia in later life, but we haven’t known if TBI affects cognitive function, causes cognitive decline that has not progressed to the point of severity with Alzheimer’s or dementia,” she added.

Being able to study the impact of TBI in monozygotic twins gives this study a unique strength, she noted.

“The important thing about this is that they are monozygotic twins, and we know they shared a lot of early life exposure, and almost 100% genetics,” Dr. Chanti-Ketterl said.

The study was published online in Neurology.

For the study, the investigators assessed 8,662 participants born between 1917 and 1927 who were part of the National Academy of Sciences National Research Council’s Twin Registry. The registry is composed of male veterans of World War II with a history of TBI, as reported by themselves or a caregiver.

The men were followed up for many years as part of the registry, but cognitive assessment only began in the 1990s. They were followed up at four different time points, at which time the Telephone Interview for Cognitive Status (TICS-m), an alternative to the Mini-Mental State Examination that must be given in person, was administered.

A total of 25% of participants had experienced concussion in their lifetime. Of this cohort, there were 589 pairs of monozygotic twins who were discordant (one twin had TBI and the other had not).

Among the monozygotic twin cohort, a history of any TBI and being older than age 24 at the time of TBI were associated with lower TICS-m scores.

A twin who experienced TBI after age 24 scored 0.59 points lower on the TICS-m at age 70 than his twin with no TBI, and cognitive function declined faster, by 0.05 points per year.
 

First study of its kind

Holly Elser, MD, PhD, MPH, an epidemiologist and resident physician in neurology at the University of Pennsylvania, Philadelphia, and coauthor of an accompanying editorial, said in an interview that the study’s twin design was a definite strength.

“There are lots of papers that have remarked on the apparent association between head injury and subsequent dementia or cognitive decline, but to my knowledge, this is one of the first, if not the first, to use a twin study design, which has the unique advantage of having better control over early life and genetic factors than would ever typically be possible in a dataset of unrelated adults,” said Dr. Elser.

She added that the study findings “strengthen our understanding of the relationship between TBI and later cognitive decline, so I think there is an etiologic value to the study.”

However, Dr. Elser noted that the composition of the study population may limit the extent to which the results apply to contemporary populations.

“This was a population of White male twins born between 1917 and 1927,” she noted. “However, does the experience of people who were in the military generalize to civilian populations? Are twins representative of the general population or are they unique in terms of their risk factors?”

It is always important to emphasize inclusivity in clinical research, and in dementia research in particular, Dr. Elser added.

“There are many examples of instances where racialized and otherwise economically marginalized groups have been excluded from analysis, which is problematic because there are already economically and socially marginalized groups who disproportionately bear the brunt of dementia.

“This is not a criticism of the authors’ work, that their data didn’t include a more diverse patient base, but I think it is an important reminder that we should always interpret study findings within the limitations of the data. It’s a reminder to be thoughtful about taking explicit steps to include more diverse groups in future research,” she said.

The study was funded by the National Institute on Aging/National Institutes of Health and the Department of Defense. Dr. Chanti-Ketterl and Dr. Elser have reported no relevant financial relationships.

A version of this article appeared on Medscape.com.

A newly published scientific statement from the American Heart Association focuses on the impact of aggressive low-density lipoprotein cholesterol (LDL-C) lowering on the risk for dementia and hemorrhagic stroke.

“The brain is the body’s most cholesterol-rich organ, and some have questioned whether aggressive LDL-C lowering induces abnormal structural and functional changes,” the writing group, led by Larry Goldstein, MD, chair, department of neurology, University of Kentucky, Lexington, points out.

The 39-page AHA scientific statement, titled “Aggressive LDL-C Lowering and the Brain: Impact on Risk for Dementia and Hemorrhagic Stroke,” was published online in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

The objective was to evaluate contemporary evidence that either supports or refutes the conclusion that aggressive LDL-C lowering or lipid lowering exerts toxic effects on the brain, leading to cognitive impairment or dementia or hemorrhagic stroke.

The eight-member writing group used literature reviews, references to published clinical and epidemiology studies, clinical and public health guidelines, authoritative statements, and expert opinion to summarize the latest evidence and identify gaps in current knowledge.

They reached four main conclusions:

• First, the available data “consistently” show that LDL-C lowering reduces the risk of atherosclerotic cardiovascular disease-related events in high-risk groups.
• Second, although some older retrospective, case-control, and prospective longitudinal studies suggest that statins and LDL-C lowering are associated with cognitive impairment or dementia, the “preponderance” of observational studies and data from randomized trials do not support this conclusion, at least among trials with median follow-up of up to 6 years. The group says additional studies are needed to ensure cognitive safety over longer periods of time. For now, contemporary guidelines recommending the risk-stratified attainment of lipid-lowering goals are “reasonable,” they conclude.
• Third, the risk for hemorrhagic stroke associated with statin therapy in patients without a history of cerebrovascular disease is “small and consistently nonsignificant.” They found no evidence that PCSK9 inhibitors or ezetimibe (Zetia) increases bleeding risk. Further, there is “no indication” that patients or populations with lifelong low LDL-C have enhanced vulnerability to hemorrhagic stroke, and there is “little evidence” that achieving very low levels of LDL-C increases that risk. What is clear, the writing group says, is that lower LDL-C levels correlate with lower risk of overall stroke and stroke recurrence, mostly related to a reduction in ischemic stroke. “Concern about hemorrhagic stroke risk should not deter a clinician from treating LDL-C to guideline-recommended risk-stratified targets,” the writing group says.
• Fourth, the group notes that data reflecting the risk of hemorrhagic stroke with statin therapy among patients with a history of hemorrhagic stroke are not robust. PCSK9 inhibitors have not been adequately tested in patients with prior intracerebral hemorrhage. Lipid lowering in these populations requires more focused study.

The research had no commercial funding. A list of disclosures for the writing group is available with the original article.

A version of this article appeared on Medscape.com.

A newly published scientific statement from the American Heart Association focuses on the impact of aggressive low-density lipoprotein cholesterol (LDL-C) lowering on the risk for dementia and hemorrhagic stroke.

“The brain is the body’s most cholesterol-rich organ, and some have questioned whether aggressive LDL-C lowering induces abnormal structural and functional changes,” the writing group, led by Larry Goldstein, MD, chair, department of neurology, University of Kentucky, Lexington, points out.

The 39-page AHA scientific statement, titled “Aggressive LDL-C Lowering and the Brain: Impact on Risk for Dementia and Hemorrhagic Stroke,” was published online in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

The objective was to evaluate contemporary evidence that either supports or refutes the conclusion that aggressive LDL-C lowering or lipid lowering exerts toxic effects on the brain, leading to cognitive impairment or dementia or hemorrhagic stroke.

The eight-member writing group used literature reviews, references to published clinical and epidemiology studies, clinical and public health guidelines, authoritative statements, and expert opinion to summarize the latest evidence and identify gaps in current knowledge.

They reached four main conclusions:

• First, the available data “consistently” show that LDL-C lowering reduces the risk of atherosclerotic cardiovascular disease-related events in high-risk groups.
• Second, although some older retrospective, case-control, and prospective longitudinal studies suggest that statins and LDL-C lowering are associated with cognitive impairment or dementia, the “preponderance” of observational studies and data from randomized trials do not support this conclusion, at least among trials with median follow-up of up to 6 years. The group says additional studies are needed to ensure cognitive safety over longer periods of time. For now, contemporary guidelines recommending the risk-stratified attainment of lipid-lowering goals are “reasonable,” they conclude.
• Third, the risk for hemorrhagic stroke associated with statin therapy in patients without a history of cerebrovascular disease is “small and consistently nonsignificant.” They found no evidence that PCSK9 inhibitors or ezetimibe (Zetia) increases bleeding risk. Further, there is “no indication” that patients or populations with lifelong low LDL-C have enhanced vulnerability to hemorrhagic stroke, and there is “little evidence” that achieving very low levels of LDL-C increases that risk. What is clear, the writing group says, is that lower LDL-C levels correlate with lower risk of overall stroke and stroke recurrence, mostly related to a reduction in ischemic stroke. “Concern about hemorrhagic stroke risk should not deter a clinician from treating LDL-C to guideline-recommended risk-stratified targets,” the writing group says.
• Fourth, the group notes that data reflecting the risk of hemorrhagic stroke with statin therapy among patients with a history of hemorrhagic stroke are not robust. PCSK9 inhibitors have not been adequately tested in patients with prior intracerebral hemorrhage. Lipid lowering in these populations requires more focused study.

The research had no commercial funding. A list of disclosures for the writing group is available with the original article.

A version of this article appeared on Medscape.com.

A newly published scientific statement from the American Heart Association focuses on the impact of aggressive low-density lipoprotein cholesterol (LDL-C) lowering on the risk for dementia and hemorrhagic stroke.

“The brain is the body’s most cholesterol-rich organ, and some have questioned whether aggressive LDL-C lowering induces abnormal structural and functional changes,” the writing group, led by Larry Goldstein, MD, chair, department of neurology, University of Kentucky, Lexington, points out.

The 39-page AHA scientific statement, titled “Aggressive LDL-C Lowering and the Brain: Impact on Risk for Dementia and Hemorrhagic Stroke,” was published online in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

The objective was to evaluate contemporary evidence that either supports or refutes the conclusion that aggressive LDL-C lowering or lipid lowering exerts toxic effects on the brain, leading to cognitive impairment or dementia or hemorrhagic stroke.

The eight-member writing group used literature reviews, references to published clinical and epidemiology studies, clinical and public health guidelines, authoritative statements, and expert opinion to summarize the latest evidence and identify gaps in current knowledge.

They reached four main conclusions:

• First, the available data “consistently” show that LDL-C lowering reduces the risk of atherosclerotic cardiovascular disease-related events in high-risk groups.
• Second, although some older retrospective, case-control, and prospective longitudinal studies suggest that statins and LDL-C lowering are associated with cognitive impairment or dementia, the “preponderance” of observational studies and data from randomized trials do not support this conclusion, at least among trials with median follow-up of up to 6 years. The group says additional studies are needed to ensure cognitive safety over longer periods of time. For now, contemporary guidelines recommending the risk-stratified attainment of lipid-lowering goals are “reasonable,” they conclude.
• Third, the risk for hemorrhagic stroke associated with statin therapy in patients without a history of cerebrovascular disease is “small and consistently nonsignificant.” They found no evidence that PCSK9 inhibitors or ezetimibe (Zetia) increases bleeding risk. Further, there is “no indication” that patients or populations with lifelong low LDL-C have enhanced vulnerability to hemorrhagic stroke, and there is “little evidence” that achieving very low levels of LDL-C increases that risk. What is clear, the writing group says, is that lower LDL-C levels correlate with lower risk of overall stroke and stroke recurrence, mostly related to a reduction in ischemic stroke. “Concern about hemorrhagic stroke risk should not deter a clinician from treating LDL-C to guideline-recommended risk-stratified targets,” the writing group says.
• Fourth, the group notes that data reflecting the risk of hemorrhagic stroke with statin therapy among patients with a history of hemorrhagic stroke are not robust. PCSK9 inhibitors have not been adequately tested in patients with prior intracerebral hemorrhage. Lipid lowering in these populations requires more focused study.

The research had no commercial funding. A list of disclosures for the writing group is available with the original article.

A version of this article appeared on Medscape.com.

Lecanemab (Lequembi, Esai), an amyloid-beta–directed antibody therapy, is approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD). But exactly how the drug clears amyloid-beta wasn’t clear.

Now new research suggests the drug, which was approved by the FDA in January, targets a particular molecular cascade, the plasma contact system, which drives amyloid-beta toxicity.

The investigators tested the effectiveness of various forms of amyloid-beta in activating the plasma contact system and found that amyloid-beta protofibrils, known to be the most toxic form of amyloid-beta, promoted the activation of this molecular cascade and that lecanemab inhibited pathway activation.

“In our study, we looked at lecanemab and found it can block the activation of the contact system, which could be one of the reasons that it works so well for AD,” study coinvestigator Erin Norris, PhD, research associate professor, Rockefeller University, New York, said in an interview.

The study was published online in the Proceedings of the National Academy of Science.
 

Unknown mechanism

“Many years ago, we started looking at the involvement of vascular dysfunction in AD,” Dr. Norris said. “We wanted to see whether or not irregular blood clotting or problems with blood flow was problematic in Alzheimer’s patients.”

The researchers found that fibrin, a major component involved in blood clotting, can extravasate into the brain.

“The blood-brain barrier can break down in Alzheimer’s, so things from the blood can move into the brain and deposit there,” she added. Fibrin then interacts with amyloid-beta, the major pathogenic protein in AD.

Dr. Norris explained that fibrin clots can form in two different ways. One is through the normal process that occurs when there’s an injury and bleeding. The second is through intrinsic clotting, which takes place through the contact system.

“We started looking into this system and found that the plasma of Alzheimer’s patients showed irregular levels of these enzymes and proteins that are part of the intrinsic clotting system compared to those of normal controls,” said Dr. Norris.

“This paper was an extension of years studying this pathway and these mechanisms. It was also inspired by the approval of lecanemab and its release for use in Alzheimer’s patients,” she added.

In previous research, the same researchers found that amyloid-beta has different forms. “It’s normally soluble, and it’s a very tiny molecule,” Dr. Norris said. “But over time, and in different situations, it can start to aggregate, becoming bigger and bigger.”
 

Implications beyond Alzheimer’s

Postmortem tissue analysis has found fibrillar plaques that are “clumped together.” These are insoluble and hard to get rid of, she said. “Protofibrils are the step before amyloid-beta forms fibrils and are considered to be the most toxic form, although the mechanism behind why it’s so toxic is not understood.”

Previous research has already shown that amyloid-beta can activate the contact system. The contact system has two “arms,” the first of which is involved with clotting, and the second with inflammation, Dr. Norris said. In fact, it’s the plasma contact system that links vascular and inflammatory pathways.

The plasma contact system leads to the clotting of fibrin, Dr. Norris continued. It activates factor XII, which leads to blood clotting by binding to coagulation factor XI.

The contact system also causes inflammation – the second “arm.” Bradykinin, a potent inflammatory molecule, is released by binding to high-molecular-weight kininogen (HK). In addition to inflammation, bradykinin can cause edema and blood-brain barrier permeability.

Although it’s been known that amyloid-beta can activate the contact system, the particular form of amyloid-beta implicated in this cascade has not been identified. And so, the researchers incubated amyloid-beta42 with human plasma, testing various types of amyloid-beta – monomers, oligomers, protofibrils, and fibrils – to see which would activate the contact system.

Amyloid-beta protofibrils promoted the activation of the contact system, as evidenced by several reactions, including activation of factor XII, while other forms of amyloid-beta did not. HK also “bound tightly” to amyloid-beta protofibrils, with “weaker” binding to other amyloid-beta species, the authors reported, confirming that amyloid-beta protofibrils bind to HK and factor XII.

Bradykinin levels were increased by amyloid-beta protofibrils, which also induced faster clotting, compared with other forms of amyloid-beta.

The researchers introduced lecanemab into the picture and found it “dramatically inhibited” contact system activation induced by amyloid-beta protofibrils. For example, it blocked the binding of factor XII to amyloid-beta. By contrast, human IgG (which the researchers used as a control) had no effect.

Additionally, lecanemab also prevented accelerated intrinsic coagulation in normal human plasma mediated by amyloid-beta protofibril.

Senior author Sidney Strickland, PhD, the Zachary and Elizabeth M. Fisher professor in Alzheimer’s and neurodegenerative disease, Rockefeller University, said in an interview: “One of the strong motivators for conducting this study was the fact that this drug, which is effective in AD, targets this specific form of amyloid-beta; but no one knows why it›s more toxic. We thought we could see if we could tie it to what we›re working on, and we found it ties in beautifully.”

The findings have implications that go beyond AD, Dr. Strickland said. “The contact system is implicated in lots of different pathologies, including sickle cell anemia, sepsis, inflammatory bowel disease, and so on.” Blocking the contact system might be a helpful approach in these conditions too.
 

Innovative, plausible, but still preliminary

In a comment, Heather M. Snyder, PhD, vice president of medical and scientific relations at the Alzheimer’s Association, called the investigation “innovative,” with ideas that are “certainly plausible.” However, “at this time, the work is preliminary and not conclusive.”

The hypothesized mechanisms for why amyloid (lecanemab’s target) is toxic to the brain “does incorporate important AD-related brain changes that have been observed in other studies, including inflammatory/immune changes and vascular-related changes,” said Dr. Snyder, who was not involved with the current study.

However, “additional studies that look both in model systems and in humans are needed to further illuminate these relationships,” Dr. Snyder said.

The study was supported by grants from the National Institutes of Health as well as the Robertson Therapeutic Development Fund, Samuel Newhouse Foundation, John A. Herrmann, and the May and Samuel Rudin Family Foundation. Dr. Norris, Dr. Strickland, and Dr. Snyder declared no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Lecanemab (Lequembi, Esai), an amyloid-beta–directed antibody therapy, is approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD). But exactly how the drug clears amyloid-beta wasn’t clear.

Now new research suggests the drug, which was approved by the FDA in January, targets a particular molecular cascade, the plasma contact system, which drives amyloid-beta toxicity.

The investigators tested the effectiveness of various forms of amyloid-beta in activating the plasma contact system and found that amyloid-beta protofibrils, known to be the most toxic form of amyloid-beta, promoted the activation of this molecular cascade and that lecanemab inhibited pathway activation.

“In our study, we looked at lecanemab and found it can block the activation of the contact system, which could be one of the reasons that it works so well for AD,” study coinvestigator Erin Norris, PhD, research associate professor, Rockefeller University, New York, said in an interview.

The study was published online in the Proceedings of the National Academy of Science.
 

Unknown mechanism

“Many years ago, we started looking at the involvement of vascular dysfunction in AD,” Dr. Norris said. “We wanted to see whether or not irregular blood clotting or problems with blood flow was problematic in Alzheimer’s patients.”

The researchers found that fibrin, a major component involved in blood clotting, can extravasate into the brain.

“The blood-brain barrier can break down in Alzheimer’s, so things from the blood can move into the brain and deposit there,” she added. Fibrin then interacts with amyloid-beta, the major pathogenic protein in AD.

Dr. Norris explained that fibrin clots can form in two different ways. One is through the normal process that occurs when there’s an injury and bleeding. The second is through intrinsic clotting, which takes place through the contact system.

“We started looking into this system and found that the plasma of Alzheimer’s patients showed irregular levels of these enzymes and proteins that are part of the intrinsic clotting system compared to those of normal controls,” said Dr. Norris.

“This paper was an extension of years studying this pathway and these mechanisms. It was also inspired by the approval of lecanemab and its release for use in Alzheimer’s patients,” she added.

In previous research, the same researchers found that amyloid-beta has different forms. “It’s normally soluble, and it’s a very tiny molecule,” Dr. Norris said. “But over time, and in different situations, it can start to aggregate, becoming bigger and bigger.”
 

Implications beyond Alzheimer’s

Postmortem tissue analysis has found fibrillar plaques that are “clumped together.” These are insoluble and hard to get rid of, she said. “Protofibrils are the step before amyloid-beta forms fibrils and are considered to be the most toxic form, although the mechanism behind why it’s so toxic is not understood.”

Previous research has already shown that amyloid-beta can activate the contact system. The contact system has two “arms,” the first of which is involved with clotting, and the second with inflammation, Dr. Norris said. In fact, it’s the plasma contact system that links vascular and inflammatory pathways.

The plasma contact system leads to the clotting of fibrin, Dr. Norris continued. It activates factor XII, which leads to blood clotting by binding to coagulation factor XI.

The contact system also causes inflammation – the second “arm.” Bradykinin, a potent inflammatory molecule, is released by binding to high-molecular-weight kininogen (HK). In addition to inflammation, bradykinin can cause edema and blood-brain barrier permeability.

Although it’s been known that amyloid-beta can activate the contact system, the particular form of amyloid-beta implicated in this cascade has not been identified. And so, the researchers incubated amyloid-beta42 with human plasma, testing various types of amyloid-beta – monomers, oligomers, protofibrils, and fibrils – to see which would activate the contact system.

Amyloid-beta protofibrils promoted the activation of the contact system, as evidenced by several reactions, including activation of factor XII, while other forms of amyloid-beta did not. HK also “bound tightly” to amyloid-beta protofibrils, with “weaker” binding to other amyloid-beta species, the authors reported, confirming that amyloid-beta protofibrils bind to HK and factor XII.

Bradykinin levels were increased by amyloid-beta protofibrils, which also induced faster clotting, compared with other forms of amyloid-beta.

The researchers introduced lecanemab into the picture and found it “dramatically inhibited” contact system activation induced by amyloid-beta protofibrils. For example, it blocked the binding of factor XII to amyloid-beta. By contrast, human IgG (which the researchers used as a control) had no effect.

Additionally, lecanemab also prevented accelerated intrinsic coagulation in normal human plasma mediated by amyloid-beta protofibril.

Senior author Sidney Strickland, PhD, the Zachary and Elizabeth M. Fisher professor in Alzheimer’s and neurodegenerative disease, Rockefeller University, said in an interview: “One of the strong motivators for conducting this study was the fact that this drug, which is effective in AD, targets this specific form of amyloid-beta; but no one knows why it›s more toxic. We thought we could see if we could tie it to what we›re working on, and we found it ties in beautifully.”

The findings have implications that go beyond AD, Dr. Strickland said. “The contact system is implicated in lots of different pathologies, including sickle cell anemia, sepsis, inflammatory bowel disease, and so on.” Blocking the contact system might be a helpful approach in these conditions too.
 

Innovative, plausible, but still preliminary

In a comment, Heather M. Snyder, PhD, vice president of medical and scientific relations at the Alzheimer’s Association, called the investigation “innovative,” with ideas that are “certainly plausible.” However, “at this time, the work is preliminary and not conclusive.”

The hypothesized mechanisms for why amyloid (lecanemab’s target) is toxic to the brain “does incorporate important AD-related brain changes that have been observed in other studies, including inflammatory/immune changes and vascular-related changes,” said Dr. Snyder, who was not involved with the current study.

However, “additional studies that look both in model systems and in humans are needed to further illuminate these relationships,” Dr. Snyder said.

The study was supported by grants from the National Institutes of Health as well as the Robertson Therapeutic Development Fund, Samuel Newhouse Foundation, John A. Herrmann, and the May and Samuel Rudin Family Foundation. Dr. Norris, Dr. Strickland, and Dr. Snyder declared no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Lecanemab (Lequembi, Esai), an amyloid-beta–directed antibody therapy, is approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD). But exactly how the drug clears amyloid-beta wasn’t clear.

Now new research suggests the drug, which was approved by the FDA in January, targets a particular molecular cascade, the plasma contact system, which drives amyloid-beta toxicity.

The investigators tested the effectiveness of various forms of amyloid-beta in activating the plasma contact system and found that amyloid-beta protofibrils, known to be the most toxic form of amyloid-beta, promoted the activation of this molecular cascade and that lecanemab inhibited pathway activation.

“In our study, we looked at lecanemab and found it can block the activation of the contact system, which could be one of the reasons that it works so well for AD,” study coinvestigator Erin Norris, PhD, research associate professor, Rockefeller University, New York, said in an interview.

The study was published online in the Proceedings of the National Academy of Science.
 

Unknown mechanism

“Many years ago, we started looking at the involvement of vascular dysfunction in AD,” Dr. Norris said. “We wanted to see whether or not irregular blood clotting or problems with blood flow was problematic in Alzheimer’s patients.”

The researchers found that fibrin, a major component involved in blood clotting, can extravasate into the brain.

“The blood-brain barrier can break down in Alzheimer’s, so things from the blood can move into the brain and deposit there,” she added. Fibrin then interacts with amyloid-beta, the major pathogenic protein in AD.

Dr. Norris explained that fibrin clots can form in two different ways. One is through the normal process that occurs when there’s an injury and bleeding. The second is through intrinsic clotting, which takes place through the contact system.

“We started looking into this system and found that the plasma of Alzheimer’s patients showed irregular levels of these enzymes and proteins that are part of the intrinsic clotting system compared to those of normal controls,” said Dr. Norris.

“This paper was an extension of years studying this pathway and these mechanisms. It was also inspired by the approval of lecanemab and its release for use in Alzheimer’s patients,” she added.

In previous research, the same researchers found that amyloid-beta has different forms. “It’s normally soluble, and it’s a very tiny molecule,” Dr. Norris said. “But over time, and in different situations, it can start to aggregate, becoming bigger and bigger.”
 

Implications beyond Alzheimer’s

Postmortem tissue analysis has found fibrillar plaques that are “clumped together.” These are insoluble and hard to get rid of, she said. “Protofibrils are the step before amyloid-beta forms fibrils and are considered to be the most toxic form, although the mechanism behind why it’s so toxic is not understood.”

Previous research has already shown that amyloid-beta can activate the contact system. The contact system has two “arms,” the first of which is involved with clotting, and the second with inflammation, Dr. Norris said. In fact, it’s the plasma contact system that links vascular and inflammatory pathways.

The plasma contact system leads to the clotting of fibrin, Dr. Norris continued. It activates factor XII, which leads to blood clotting by binding to coagulation factor XI.

The contact system also causes inflammation – the second “arm.” Bradykinin, a potent inflammatory molecule, is released by binding to high-molecular-weight kininogen (HK). In addition to inflammation, bradykinin can cause edema and blood-brain barrier permeability.

Although it’s been known that amyloid-beta can activate the contact system, the particular form of amyloid-beta implicated in this cascade has not been identified. And so, the researchers incubated amyloid-beta42 with human plasma, testing various types of amyloid-beta – monomers, oligomers, protofibrils, and fibrils – to see which would activate the contact system.

Amyloid-beta protofibrils promoted the activation of the contact system, as evidenced by several reactions, including activation of factor XII, while other forms of amyloid-beta did not. HK also “bound tightly” to amyloid-beta protofibrils, with “weaker” binding to other amyloid-beta species, the authors reported, confirming that amyloid-beta protofibrils bind to HK and factor XII.

Bradykinin levels were increased by amyloid-beta protofibrils, which also induced faster clotting, compared with other forms of amyloid-beta.

The researchers introduced lecanemab into the picture and found it “dramatically inhibited” contact system activation induced by amyloid-beta protofibrils. For example, it blocked the binding of factor XII to amyloid-beta. By contrast, human IgG (which the researchers used as a control) had no effect.

Additionally, lecanemab also prevented accelerated intrinsic coagulation in normal human plasma mediated by amyloid-beta protofibril.

Senior author Sidney Strickland, PhD, the Zachary and Elizabeth M. Fisher professor in Alzheimer’s and neurodegenerative disease, Rockefeller University, said in an interview: “One of the strong motivators for conducting this study was the fact that this drug, which is effective in AD, targets this specific form of amyloid-beta; but no one knows why it›s more toxic. We thought we could see if we could tie it to what we›re working on, and we found it ties in beautifully.”

The findings have implications that go beyond AD, Dr. Strickland said. “The contact system is implicated in lots of different pathologies, including sickle cell anemia, sepsis, inflammatory bowel disease, and so on.” Blocking the contact system might be a helpful approach in these conditions too.
 

Innovative, plausible, but still preliminary

In a comment, Heather M. Snyder, PhD, vice president of medical and scientific relations at the Alzheimer’s Association, called the investigation “innovative,” with ideas that are “certainly plausible.” However, “at this time, the work is preliminary and not conclusive.”

The hypothesized mechanisms for why amyloid (lecanemab’s target) is toxic to the brain “does incorporate important AD-related brain changes that have been observed in other studies, including inflammatory/immune changes and vascular-related changes,” said Dr. Snyder, who was not involved with the current study.

However, “additional studies that look both in model systems and in humans are needed to further illuminate these relationships,” Dr. Snyder said.

The study was supported by grants from the National Institutes of Health as well as the Robertson Therapeutic Development Fund, Samuel Newhouse Foundation, John A. Herrmann, and the May and Samuel Rudin Family Foundation. Dr. Norris, Dr. Strickland, and Dr. Snyder declared no relevant financial relationships.

A version of this article first appeared on Medscape.com.