New and Noteworthy Information—February 2017

Concussions may accelerate Alzheimer's disease-related brain atrophy and cognitive decline in people who are at genetic risk for the condition, according to a study published online ahead of print January 11 in Brain. A total of 160 Iraq and Afghanistan war veterans between the ages of 19 and 58, were included in this study. Among males with mild traumatic brain injury, high genetic risk for Alzheimer's disease was associated with cortical thinning as a function of time since injury. A moderated mediation analysis showed that mild traumatic brain injury and high genetic risk indirectly influenced episodic memory performance through cortical thickness. The findings highlight the importance of documenting head injuries, as they may interact with genetic risk to produce negative long-term health consequences, according to the authors.

 
During pregnancy, Asian women with poor sleep quality or short nocturnal sleep duration exhibit abnormal glucose regulation, according to a study published online ahead of print November 14 in Sleep. In all, 686 women with a singleton pregnancy attended a clinic visit at 26 to 28 weeks of gestation, as part of the Growing Up in Singapore Towards healthy Outcomes mother-offspring cohort study. Self-reported sleep quality and sleep duration were assessed using the Pittsburgh Sleep Quality Index. Two hundred ninety-six women had poor sleep quality, and 77 women were categorized as short sleepers. One hundred thirty-one women were diagnosed with gestational diabetes mellitus. Poor sleep quality and short nocturnal sleep duration were independently associated with increased risk of gestational diabetes mellitus.  

 
Heightened activity in the amygdala is associated with a greater risk of heart disease and stroke, according to a study published online ahead of print January 12 in Lancet. Investigators followed 293 people age 30 or older without known cardiovascular disease or active cancer disorders, who underwent PET/CT scans between January 1, 2005, and December 31, 2008. Twenty-two people had a cardiovascular disease event during mean follow-up of 3.7 years. Amygdalar activity was associated with increased bone-marrow activity, arterial inflammation, and risk of cardiovascular disease events. In a cross-sectional study of 13 patients who underwent psychometric analysis, amygdalar activity was significantly associated with arterial inflammation, and perceived stress was associated with amygdalar activity, arterial inflammation, and C-reactive protein.  

 
Developing hypertension at an older age may protect against dementia, according to a study published online January 16 in Alzheimer's & Dementia. The study included participants from a population-based longitudinal study of people age 90 and older (The 90+ Study) who were survivors of the Leisure World Cohort Study. Researchers estimated hypertension onset age using patient-reported information. A total of 559 participants without dementia were followed every six months for up to 10 years. Two hundred twenty-four participants developed dementia during follow-up. Compared with participants without hypertension, participants whose hypertension onset age was between 80 and 89 had a lower dementia risk, and participants with an onset age of 90 and older had the lowest risk.

 
Living close to heavy traffic is associated with a higher incidence of dementia, but not Parkinson's disease or multiple sclerosis, according to a study published online ahead of print January 4 in Lancet. Researchers assembled two population-based cohorts that included adults who resided in Ontario, Canada. Between 2001 and 2012, researchers identified 243,611 incident cases of dementia, 31,577 cases of Parkinson's disease, and 9,247 cases of multiple sclerosis. Dementia risk decreased as people lived farther away from a main road. Overall, there was a 7% higher risk of dementia among people living within 50 meters of a main road, a 4% higher risk at 50 to 100 meters, and a 2% higher risk at 101 to 200 meters. There was no increase in risk in those living more than 200 meters away.

 
The US Preventive Services Task Force (USPSTF) recommends that all women who are planning to become or capable of becoming pregnant take a daily supplement containing 0.4 mg to 0.8 mg of folic acid, according to a recommendation statement published in the January 10 issue of JAMA. In 2009, the USPSTF reviewed the effectiveness of folic acid supplementation in women of childbearing age for the prevention of neural tube defects in infants. The current review assessed new evidence on the benefits and harms of folic acid supplementation. The USPSTF evaluated one randomized clinical trial, two cohort studies, eight case-control studies, and two publications from the previous USPSTF review. The task force found no new substantial evidence about the benefits and harms of folic acid supplementation. The USPSTF reaffirmed its 2009 recommendation.  

 
Low serum 25-hydroxyvitamin D (25[OH]D] concentration is associated with markedly higher risk of frequent headache in men, according to a study published January 3 in Scientific Reports. The study consisted of 2,601 men from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study in eastern Finland. Cross-sectional associations with prevalence of self-reported frequent headache were estimated with adjusted odds ratios. Participants' average serum 25(OH)D concentration was 43.4 nmol/L. A total of 250 men reported frequent (ie, weekly or daily) headache. The average serum 25(OH)D concentration among those with frequent headache was 38.3 nmol/L and 43.9 nmol/L among those without frequent headache, after adjustment for age and year and month of blood draw. After multivariable adjustments, those in the lowest versus the highest serum 25(OH)D quartile had 113% higher odds for frequent headache.

Moderate postlunch napping is associated with better cognition in Chinese older adults, according to a cross-sectional study published online ahead of print December 20, 2016, in the Journal of the American Geriatrics Society. A total of 2,974 people age 65 and older from the China Health and Retirement Longitudinal Study were included in this study. Investigators conducted interview-based cognitive assessments of orientation and attention, episodic memory, and visuospatial abilities. Patients reported their postlunch napping habits. Postlunch napping was reported in 57.7% of participants (mean duration, 63 minutes). Cognitive function was significantly associated with napping. Moderate nappers had better overall cognition than nonnappers or extended nappers. Nonnappers also had significantly poorer cognition than short nappers.  

 
Physical exercise may be effective in the prevention of dementia, according to a study published in the January issue of the Journal of Alzheimer's Disease. Researchers assessed the interactive relationship of APOE genotype and physical exercise on dementia risk over a five-year period in 1,646 older adults from the Canadian Study of Health and Aging who were dementia-free at baseline. Physical exercise moderated the relationship between genotype and dementia. For APOE  ε4 noncarriers, the odds of developing dementia were higher in nonexercisers than in exercisers (odds ratio, 1.98). For APOE  ε4 carriers, the odds of developing dementia were not significantly different between nonexercisers and exercisers. "Given that most individuals are not at genetic risk, physical exercise may be an effective prevention strategy," the researchers concluded.

 
Lower adherence to a Mediterranean-type diet is predictive of total brain atrophy over a three-year period, according to a study published online ahead of print January 4 in Neurology. Researchers focused on total brain volume, gray matter volume, and cortical thickness. Investigators gathered information on the eating habits of 967 Scottish people at age 70. In regression models adjusting for relevant demographic and physical health indicators, lower adherence to the Mediterranean-type diet was associated with greater three-year reduction in total brain volume. Cross-sectional associations between Mediterranean-type diet and baseline MRI measures in 562 participants were not significant. Targeted analyses of meat and fish consumption did not replicate previous associations with total brain volume or total gray matter volume.

 
Children who sustain concussions have a 35% smaller neural response to pitch on average, according to a study published online ahead of print December 22, 2016, in Scientific Reports. Researchers studied 40 children with concussion and a control group. Children with concussion exhibited a signature neural profile. Children had worse representation of the fundamental frequency and smaller, more sluggish neural responses. As the children recovered from their head injuries, their ability to process pitch returned to normal. Neural processing of sound correctly identified 90% of concussion cases and cleared 95% of control cases, suggesting this approach has practical potential as a scalable biologic marker for sports-related concussion and other mild traumatic brain injuries.

People who are homeless sleep less and are more likely to have insomnia and daytime fatigue than people in the general population, according to a study published online ahead of print December 27, 2016, in JAMA Internal Medicine. Investigators analyzed survey responses from 3,453 people who were homeless (2,068 men; mean age, 39.8) and compared them with responses from individuals in the general population. Homeless people reported significantly shorter total sleep time than the general population (6 h 31 min vs 7 h 9 min). Eight percent reported less than four hours of total sleep time over the past 24 hours, compared with 3% of the general population. Homeless women were twice as likely as men to report that they slept less than four hours. Furthermore, insomnia was reported by 41% of homeless people, compared with 19% of controls.

—Kimberly Williams

Concussions may accelerate Alzheimer's disease-related brain atrophy and cognitive decline in people who are at genetic risk for the condition, according to a study published online ahead of print January 11 in Brain. A total of 160 Iraq and Afghanistan war veterans between the ages of 19 and 58, were included in this study. Among males with mild traumatic brain injury, high genetic risk for Alzheimer's disease was associated with cortical thinning as a function of time since injury. A moderated mediation analysis showed that mild traumatic brain injury and high genetic risk indirectly influenced episodic memory performance through cortical thickness. The findings highlight the importance of documenting head injuries, as they may interact with genetic risk to produce negative long-term health consequences, according to the authors.

 
During pregnancy, Asian women with poor sleep quality or short nocturnal sleep duration exhibit abnormal glucose regulation, according to a study published online ahead of print November 14 in Sleep. In all, 686 women with a singleton pregnancy attended a clinic visit at 26 to 28 weeks of gestation, as part of the Growing Up in Singapore Towards healthy Outcomes mother-offspring cohort study. Self-reported sleep quality and sleep duration were assessed using the Pittsburgh Sleep Quality Index. Two hundred ninety-six women had poor sleep quality, and 77 women were categorized as short sleepers. One hundred thirty-one women were diagnosed with gestational diabetes mellitus. Poor sleep quality and short nocturnal sleep duration were independently associated with increased risk of gestational diabetes mellitus.  

 
Heightened activity in the amygdala is associated with a greater risk of heart disease and stroke, according to a study published online ahead of print January 12 in Lancet. Investigators followed 293 people age 30 or older without known cardiovascular disease or active cancer disorders, who underwent PET/CT scans between January 1, 2005, and December 31, 2008. Twenty-two people had a cardiovascular disease event during mean follow-up of 3.7 years. Amygdalar activity was associated with increased bone-marrow activity, arterial inflammation, and risk of cardiovascular disease events. In a cross-sectional study of 13 patients who underwent psychometric analysis, amygdalar activity was significantly associated with arterial inflammation, and perceived stress was associated with amygdalar activity, arterial inflammation, and C-reactive protein.  

 
Developing hypertension at an older age may protect against dementia, according to a study published online January 16 in Alzheimer's & Dementia. The study included participants from a population-based longitudinal study of people age 90 and older (The 90+ Study) who were survivors of the Leisure World Cohort Study. Researchers estimated hypertension onset age using patient-reported information. A total of 559 participants without dementia were followed every six months for up to 10 years. Two hundred twenty-four participants developed dementia during follow-up. Compared with participants without hypertension, participants whose hypertension onset age was between 80 and 89 had a lower dementia risk, and participants with an onset age of 90 and older had the lowest risk.

 
Living close to heavy traffic is associated with a higher incidence of dementia, but not Parkinson's disease or multiple sclerosis, according to a study published online ahead of print January 4 in Lancet. Researchers assembled two population-based cohorts that included adults who resided in Ontario, Canada. Between 2001 and 2012, researchers identified 243,611 incident cases of dementia, 31,577 cases of Parkinson's disease, and 9,247 cases of multiple sclerosis. Dementia risk decreased as people lived farther away from a main road. Overall, there was a 7% higher risk of dementia among people living within 50 meters of a main road, a 4% higher risk at 50 to 100 meters, and a 2% higher risk at 101 to 200 meters. There was no increase in risk in those living more than 200 meters away.

 
The US Preventive Services Task Force (USPSTF) recommends that all women who are planning to become or capable of becoming pregnant take a daily supplement containing 0.4 mg to 0.8 mg of folic acid, according to a recommendation statement published in the January 10 issue of JAMA. In 2009, the USPSTF reviewed the effectiveness of folic acid supplementation in women of childbearing age for the prevention of neural tube defects in infants. The current review assessed new evidence on the benefits and harms of folic acid supplementation. The USPSTF evaluated one randomized clinical trial, two cohort studies, eight case-control studies, and two publications from the previous USPSTF review. The task force found no new substantial evidence about the benefits and harms of folic acid supplementation. The USPSTF reaffirmed its 2009 recommendation.  

 
Low serum 25-hydroxyvitamin D (25[OH]D] concentration is associated with markedly higher risk of frequent headache in men, according to a study published January 3 in Scientific Reports. The study consisted of 2,601 men from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study in eastern Finland. Cross-sectional associations with prevalence of self-reported frequent headache were estimated with adjusted odds ratios. Participants' average serum 25(OH)D concentration was 43.4 nmol/L. A total of 250 men reported frequent (ie, weekly or daily) headache. The average serum 25(OH)D concentration among those with frequent headache was 38.3 nmol/L and 43.9 nmol/L among those without frequent headache, after adjustment for age and year and month of blood draw. After multivariable adjustments, those in the lowest versus the highest serum 25(OH)D quartile had 113% higher odds for frequent headache.

Moderate postlunch napping is associated with better cognition in Chinese older adults, according to a cross-sectional study published online ahead of print December 20, 2016, in the Journal of the American Geriatrics Society. A total of 2,974 people age 65 and older from the China Health and Retirement Longitudinal Study were included in this study. Investigators conducted interview-based cognitive assessments of orientation and attention, episodic memory, and visuospatial abilities. Patients reported their postlunch napping habits. Postlunch napping was reported in 57.7% of participants (mean duration, 63 minutes). Cognitive function was significantly associated with napping. Moderate nappers had better overall cognition than nonnappers or extended nappers. Nonnappers also had significantly poorer cognition than short nappers.  

 
Physical exercise may be effective in the prevention of dementia, according to a study published in the January issue of the Journal of Alzheimer's Disease. Researchers assessed the interactive relationship of APOE genotype and physical exercise on dementia risk over a five-year period in 1,646 older adults from the Canadian Study of Health and Aging who were dementia-free at baseline. Physical exercise moderated the relationship between genotype and dementia. For APOE  ε4 noncarriers, the odds of developing dementia were higher in nonexercisers than in exercisers (odds ratio, 1.98). For APOE  ε4 carriers, the odds of developing dementia were not significantly different between nonexercisers and exercisers. "Given that most individuals are not at genetic risk, physical exercise may be an effective prevention strategy," the researchers concluded.

 
Lower adherence to a Mediterranean-type diet is predictive of total brain atrophy over a three-year period, according to a study published online ahead of print January 4 in Neurology. Researchers focused on total brain volume, gray matter volume, and cortical thickness. Investigators gathered information on the eating habits of 967 Scottish people at age 70. In regression models adjusting for relevant demographic and physical health indicators, lower adherence to the Mediterranean-type diet was associated with greater three-year reduction in total brain volume. Cross-sectional associations between Mediterranean-type diet and baseline MRI measures in 562 participants were not significant. Targeted analyses of meat and fish consumption did not replicate previous associations with total brain volume or total gray matter volume.

 
Children who sustain concussions have a 35% smaller neural response to pitch on average, according to a study published online ahead of print December 22, 2016, in Scientific Reports. Researchers studied 40 children with concussion and a control group. Children with concussion exhibited a signature neural profile. Children had worse representation of the fundamental frequency and smaller, more sluggish neural responses. As the children recovered from their head injuries, their ability to process pitch returned to normal. Neural processing of sound correctly identified 90% of concussion cases and cleared 95% of control cases, suggesting this approach has practical potential as a scalable biologic marker for sports-related concussion and other mild traumatic brain injuries.

People who are homeless sleep less and are more likely to have insomnia and daytime fatigue than people in the general population, according to a study published online ahead of print December 27, 2016, in JAMA Internal Medicine. Investigators analyzed survey responses from 3,453 people who were homeless (2,068 men; mean age, 39.8) and compared them with responses from individuals in the general population. Homeless people reported significantly shorter total sleep time than the general population (6 h 31 min vs 7 h 9 min). Eight percent reported less than four hours of total sleep time over the past 24 hours, compared with 3% of the general population. Homeless women were twice as likely as men to report that they slept less than four hours. Furthermore, insomnia was reported by 41% of homeless people, compared with 19% of controls.

—Kimberly Williams

Concussions may accelerate Alzheimer's disease-related brain atrophy and cognitive decline in people who are at genetic risk for the condition, according to a study published online ahead of print January 11 in Brain. A total of 160 Iraq and Afghanistan war veterans between the ages of 19 and 58, were included in this study. Among males with mild traumatic brain injury, high genetic risk for Alzheimer's disease was associated with cortical thinning as a function of time since injury. A moderated mediation analysis showed that mild traumatic brain injury and high genetic risk indirectly influenced episodic memory performance through cortical thickness. The findings highlight the importance of documenting head injuries, as they may interact with genetic risk to produce negative long-term health consequences, according to the authors.

 
During pregnancy, Asian women with poor sleep quality or short nocturnal sleep duration exhibit abnormal glucose regulation, according to a study published online ahead of print November 14 in Sleep. In all, 686 women with a singleton pregnancy attended a clinic visit at 26 to 28 weeks of gestation, as part of the Growing Up in Singapore Towards healthy Outcomes mother-offspring cohort study. Self-reported sleep quality and sleep duration were assessed using the Pittsburgh Sleep Quality Index. Two hundred ninety-six women had poor sleep quality, and 77 women were categorized as short sleepers. One hundred thirty-one women were diagnosed with gestational diabetes mellitus. Poor sleep quality and short nocturnal sleep duration were independently associated with increased risk of gestational diabetes mellitus.  

 
Heightened activity in the amygdala is associated with a greater risk of heart disease and stroke, according to a study published online ahead of print January 12 in Lancet. Investigators followed 293 people age 30 or older without known cardiovascular disease or active cancer disorders, who underwent PET/CT scans between January 1, 2005, and December 31, 2008. Twenty-two people had a cardiovascular disease event during mean follow-up of 3.7 years. Amygdalar activity was associated with increased bone-marrow activity, arterial inflammation, and risk of cardiovascular disease events. In a cross-sectional study of 13 patients who underwent psychometric analysis, amygdalar activity was significantly associated with arterial inflammation, and perceived stress was associated with amygdalar activity, arterial inflammation, and C-reactive protein.  

 
Developing hypertension at an older age may protect against dementia, according to a study published online January 16 in Alzheimer's & Dementia. The study included participants from a population-based longitudinal study of people age 90 and older (The 90+ Study) who were survivors of the Leisure World Cohort Study. Researchers estimated hypertension onset age using patient-reported information. A total of 559 participants without dementia were followed every six months for up to 10 years. Two hundred twenty-four participants developed dementia during follow-up. Compared with participants without hypertension, participants whose hypertension onset age was between 80 and 89 had a lower dementia risk, and participants with an onset age of 90 and older had the lowest risk.

 
Living close to heavy traffic is associated with a higher incidence of dementia, but not Parkinson's disease or multiple sclerosis, according to a study published online ahead of print January 4 in Lancet. Researchers assembled two population-based cohorts that included adults who resided in Ontario, Canada. Between 2001 and 2012, researchers identified 243,611 incident cases of dementia, 31,577 cases of Parkinson's disease, and 9,247 cases of multiple sclerosis. Dementia risk decreased as people lived farther away from a main road. Overall, there was a 7% higher risk of dementia among people living within 50 meters of a main road, a 4% higher risk at 50 to 100 meters, and a 2% higher risk at 101 to 200 meters. There was no increase in risk in those living more than 200 meters away.

 
The US Preventive Services Task Force (USPSTF) recommends that all women who are planning to become or capable of becoming pregnant take a daily supplement containing 0.4 mg to 0.8 mg of folic acid, according to a recommendation statement published in the January 10 issue of JAMA. In 2009, the USPSTF reviewed the effectiveness of folic acid supplementation in women of childbearing age for the prevention of neural tube defects in infants. The current review assessed new evidence on the benefits and harms of folic acid supplementation. The USPSTF evaluated one randomized clinical trial, two cohort studies, eight case-control studies, and two publications from the previous USPSTF review. The task force found no new substantial evidence about the benefits and harms of folic acid supplementation. The USPSTF reaffirmed its 2009 recommendation.  

 
Low serum 25-hydroxyvitamin D (25[OH]D] concentration is associated with markedly higher risk of frequent headache in men, according to a study published January 3 in Scientific Reports. The study consisted of 2,601 men from the population-based Kuopio Ischaemic Heart Disease Risk Factor Study in eastern Finland. Cross-sectional associations with prevalence of self-reported frequent headache were estimated with adjusted odds ratios. Participants' average serum 25(OH)D concentration was 43.4 nmol/L. A total of 250 men reported frequent (ie, weekly or daily) headache. The average serum 25(OH)D concentration among those with frequent headache was 38.3 nmol/L and 43.9 nmol/L among those without frequent headache, after adjustment for age and year and month of blood draw. After multivariable adjustments, those in the lowest versus the highest serum 25(OH)D quartile had 113% higher odds for frequent headache.

Moderate postlunch napping is associated with better cognition in Chinese older adults, according to a cross-sectional study published online ahead of print December 20, 2016, in the Journal of the American Geriatrics Society. A total of 2,974 people age 65 and older from the China Health and Retirement Longitudinal Study were included in this study. Investigators conducted interview-based cognitive assessments of orientation and attention, episodic memory, and visuospatial abilities. Patients reported their postlunch napping habits. Postlunch napping was reported in 57.7% of participants (mean duration, 63 minutes). Cognitive function was significantly associated with napping. Moderate nappers had better overall cognition than nonnappers or extended nappers. Nonnappers also had significantly poorer cognition than short nappers.  

 
Physical exercise may be effective in the prevention of dementia, according to a study published in the January issue of the Journal of Alzheimer's Disease. Researchers assessed the interactive relationship of APOE genotype and physical exercise on dementia risk over a five-year period in 1,646 older adults from the Canadian Study of Health and Aging who were dementia-free at baseline. Physical exercise moderated the relationship between genotype and dementia. For APOE  ε4 noncarriers, the odds of developing dementia were higher in nonexercisers than in exercisers (odds ratio, 1.98). For APOE  ε4 carriers, the odds of developing dementia were not significantly different between nonexercisers and exercisers. "Given that most individuals are not at genetic risk, physical exercise may be an effective prevention strategy," the researchers concluded.

 
Lower adherence to a Mediterranean-type diet is predictive of total brain atrophy over a three-year period, according to a study published online ahead of print January 4 in Neurology. Researchers focused on total brain volume, gray matter volume, and cortical thickness. Investigators gathered information on the eating habits of 967 Scottish people at age 70. In regression models adjusting for relevant demographic and physical health indicators, lower adherence to the Mediterranean-type diet was associated with greater three-year reduction in total brain volume. Cross-sectional associations between Mediterranean-type diet and baseline MRI measures in 562 participants were not significant. Targeted analyses of meat and fish consumption did not replicate previous associations with total brain volume or total gray matter volume.

 
Children who sustain concussions have a 35% smaller neural response to pitch on average, according to a study published online ahead of print December 22, 2016, in Scientific Reports. Researchers studied 40 children with concussion and a control group. Children with concussion exhibited a signature neural profile. Children had worse representation of the fundamental frequency and smaller, more sluggish neural responses. As the children recovered from their head injuries, their ability to process pitch returned to normal. Neural processing of sound correctly identified 90% of concussion cases and cleared 95% of control cases, suggesting this approach has practical potential as a scalable biologic marker for sports-related concussion and other mild traumatic brain injuries.

People who are homeless sleep less and are more likely to have insomnia and daytime fatigue than people in the general population, according to a study published online ahead of print December 27, 2016, in JAMA Internal Medicine. Investigators analyzed survey responses from 3,453 people who were homeless (2,068 men; mean age, 39.8) and compared them with responses from individuals in the general population. Homeless people reported significantly shorter total sleep time than the general population (6 h 31 min vs 7 h 9 min). Eight percent reported less than four hours of total sleep time over the past 24 hours, compared with 3% of the general population. Homeless women were twice as likely as men to report that they slept less than four hours. Furthermore, insomnia was reported by 41% of homeless people, compared with 19% of controls.

—Kimberly Williams