New and Noteworthy Information—July 2013

In patients with arterial disease, low baseline diastolic blood pressure may correspond with increased progression of subcortical atrophy, researchers reported online ahead of print June 10 in JAMA Neurology. The association may not depend on subsequent change in blood pressure. Researchers measured blood pressure for 663 participants at baseline and at a mean of 3.9 years later. Change in brain parenchymal fraction, cortical gray matter fraction, and ventricular fraction were quantified as indicators of progression of global, cortical, and subcortical brain atrophy. Patients with lower baseline diastolic blood pressure or mean arterial pressure had more progression of subcortical atrophy. Of patients with higher baseline blood pressure, those with declining blood pressure over time had less progression of subcortical atrophy, compared with those with increasing blood pressure.

Diffusion tensor imaging (DTI) of the basal ganglia and cerebellum may accurately diagnose Parkinson’s disease and other movement disorders, according to a study published online ahead of print May 14 in Movement Disorders. Investigators studied 72 subjects with DTI at 3 T. The technique distinguished between controls and patients with movement disorder with 92% sensitivity and 88% specificity. DTI also distinguished between controls and patients with parkinsonism (93% sensitivity, 91% specificity), Parkinson’s disease and atypical parkinsonism (90% sensitivity, 100% specificity), Parkinson’s disease and multiple system atrophy (94% sensitivity, 100% specificity), Parkinson’s disease and progressive supranuclear palsy (87% sensitivity, 100% specificity), multiple system atrophy and progressive supranuclear palsy (90% sensitivity, 100% specificity), and Parkinson’s disease and essential tremor (92% sensitivity, 87% specificity).

Heading a soccer ball may be associated with abnormal white matter microstructure and poor neurocognitive performance, according to research published online ahead of print June 11 in Radiology. Thirty-seven amateur soccer players answered a questionnaire about heading in the previous 12 months and lifetime history of concussions. Investigators performed diffusion-tensor MRI on the players and evaluated their cognitive function. The players had headed a median of 432 times during the previous year. Heading was associated with lower fractional anisotropy (FA) at three locations in temporo-occipital white matter with a threshold that varied according to location. Heading more than 1,800 times per year was associated with lower levels of FA and poorer memory scores. Concussion history and demographic features were not significantly associated with FA or cognitive performance.

Restless legs syndrome (RLS) may entail an increased risk of mortality, independent of known risk factors, according to a study published online ahead of print June 12 in Neurology. Researchers conducted a prospective cohort study of 18,425 American men without diabetes, arthritis, or renal failure. RLS was assessed using standardized questions. During eight years of follow-up, 2,765 deaths occurred. In an age-adjusted model, RLS was associated with a 39% increased risk of mortality. The association between RLS and mortality was slightly attenuated after further adjustment for BMI, lifestyle factors, chronic conditions, sleep duration, and other sleep-related disorders. When patients with major chronic conditions (eg, cancer, high blood pressure, cardiovascular disease, and other comorbidities) were excluded, the adjusted hazard ratio for RLS was 1.92.

Patients with stroke who are about to undergo surgery can safely continue to take aspirin or warfarin in many instances, according to a guideline published in the May 28 Neurology. Researchers systematically reviewed the literature to assess evidence about the periprocedural management of antithrombotic drugs in patients with ischemic cerebrovascular disease. Stroke patients undergoing dental procedures should routinely continue aspirin, according to the guideline. Stroke patients undergoing invasive ocular anesthesia, cataract surgery, dermatologic procedures, transrectal ultrasound–guided prostate biopsy, spinal or epidural procedures, and carpal tunnel surgery should probably continue aspirin. Stroke patients requiring warfarin should routinely continue it when undergoing dental procedures and probably continue it for dermatologic procedures. Some patients undergoing EMG, prostate procedures, inguinal herniorrhaphy, and endothermal ablation of the great saphenous vein should possibly continue warfarin.

Exposure to pesticides or solvents could be a risk factor for Parkinson’s disease, investigators concluded in the May 28 Neurology. Researchers performed a meta-analysis of prospective cohort and case-control studies that estimated the risk of Parkinson’s disease associated with exposure to pesticides or solvents. Parkinson’s disease was associated with farming, and the association between the disease and pesticides was highly significant in the studies in which Parkinson’s disease diagnosis was self-reported. In high-quality case-control studies, exposure to any pesticides, herbicides, and solvents increased the risk of Parkinson’s disease. Exposure to paraquat or maneb/mancozeb was associated with about a twofold increase in risk. Study quality was not a source of heterogeneity among prospective studies. In case-control studies, study quality was a source of heterogeneity in risk estimates for some exposures.

Atrial fibrillation may be associated with faster cognitive decline, according to a study published online ahead of print June 5 in Neurology. Researchers studied 5,150 men and women 65 or older who did not have atrial fibrillation or a history of stroke at baseline. Atrial fibrillation was identified by examining hospital discharge records and annual ECGs. A total of 552 patients (10.7%) developed incident atrial fibrillation during a mean seven years of follow-up. Mean Modified Mini-Mental State Examination (MMMSE) scores declined faster in patients with incident atrial fibrillation than in patients without atrial fibrillation. The predicted five-year decline in mean MMMSE score from age 80 to age 85 was −6.4 points for participants without atrial fibrillation and −10.3 points for participants with incident atrial fibrillation at age 80.

The level of interleukin 17F (IL-17F) in a patient with relapsing-remitting multiple sclerosis (MS) may not predict his or her response to treatment with interferon beta, according to research published online ahead of print June 3 in JAMA Neurology. Researchers analyzed serum samples from 239 randomly selected patients treated with interferon beta-1b (250 μg) for at least two years. Using clinical and MRI criteria, the investigators found that levels of IL-17F measured at baseline and month six did not correlate with lack of response to treatment after two years. Relapses and new lesions on MRI were not associated with pretreatment serum IL-17F levels. The results did not change when patients with neutralizing antibodies were excluded. Patients with levels of IL-17F higher than 200 pg/mL had poor response and clinical or radiologic activity.

Earlier treatment with thrombolytics may be associated with reduced mortality for patients with stroke, according to data published in the June 19 JAMA. Researchers analyzed data from 58,353 patients with acute ischemic stroke who were treated with t-PA within 4.5 hours of symptom onset in 1,395 hospitals. Patients’ median age was 72, 50.3% of patients were women, and median time to treatment was 144 minutes. A total of 5,142 in-hospital deaths occurred. Faster time to treatment, in 15-minute increments, was associated with reduced in-hospital mortality, reduced symptomatic intracranial hemorrhage, increased achievement of independent ambulation at discharge, and increased discharge to home. Patient factors most strongly associated with shorter time to treatment included greater stroke severity, arrival by ambulance, and arrival during regular hours.

High serum iron levels may be associated with a decreased risk of developing Parkinson’s disease, according to a study published June 4 in PLOS Medicine. Researchers investigated three polymorphisms in the genes HFE and TMPRSS6. For each polymorphism, they performed a meta-analysis of studies investigating the genetic effect on iron levels and a meta-analysis of studies investigating the genetic effect on the risk of Parkinson’s disease. Using three Mendelian randomization analyses, the investigators estimated the effect of iron on Parkinson’s disease for the three polymorphisms. Every 10 µg/dl increase in blood iron corresponded to a 3% reduction in the risk of Parkinson’s disease. Thus, increased blood iron levels may have a protective effect against Parkinson’s disease, but the underlying mechanism remains unclear, said the researchers.

Diabetes and dementia may have a bidirectional association, according to research published online ahead of print June 10 in JAMA Internal Medicine. Investigators examined 783 older adults with diabetes who were participating in a prospective population-based study. Subjects’ mean age was 74, and their baseline Modified Mini-Mental State Examination scores were 80 or higher. Approximately 47% of subjects were African American, and 47% were female. During the 12-year follow-up, 61 participants had a reported hypoglycemic event, and 148 developed dementia. Subjects who had a hypoglycemic event had a twofold increased risk for developing dementia, compared with those who did not have a hypoglycemic event. Subjects with diabetes who developed dementia had a greater risk for having a subsequent hypoglycemic event, compared with participants who did not develop dementia.

Cardiovascular biomarkers may help identify patients with subclinical cerebral injury, according to research published online ahead of print May 9 in Stroke. A total of 1,920 subjects received a brain MRI and had their levels of N-terminal brain natriuretic peptide (NT-proBNP) and cardiac troponin T (hs-cTnT) measured. Of the total group, 1,112 had a follow-up MRI between nine and 13 years later. Individuals with the highest NT-proBNP levels had significantly more silent brain infarcts and white matter lesions on the baseline MRI and more incident silent brain infarcts and white matter lesion progression on the follow-up MRI. Individuals with the highest hs-cTnT levels had more silent brain infarcts and white matter lesions on the initial MRI and more white matter lesion progression on the follow-up MRI.

Stroke symptoms or transient ischemic attack (TIA) may be strongly associated with incident cognitive impairment, researchers concluded in a study published online ahead of print June 19 in Neurology. The investigators studied 23,830 participants without cognitive impairment or history of stroke enrolled in the Reasons for Geographic and Racial Differences in Stroke Study. Subjects reported stroke symptoms and TIA every six months and were screened annually for cognitive impairment. Among Caucasians, the odds ratio for incident cognitive impairment was 2.08 for subjects reporting at least one stroke symptom or TIA, compared with those reporting no stroke symptom or TIA. Among African Americans, the odds ratio was 1.66 using the same modeling. The magnitude of impact was largest among participants with fewer traditional stroke risk factors.

—Erik Greb
Senior Associate Editor

In patients with arterial disease, low baseline diastolic blood pressure may correspond with increased progression of subcortical atrophy, researchers reported online ahead of print June 10 in JAMA Neurology. The association may not depend on subsequent change in blood pressure. Researchers measured blood pressure for 663 participants at baseline and at a mean of 3.9 years later. Change in brain parenchymal fraction, cortical gray matter fraction, and ventricular fraction were quantified as indicators of progression of global, cortical, and subcortical brain atrophy. Patients with lower baseline diastolic blood pressure or mean arterial pressure had more progression of subcortical atrophy. Of patients with higher baseline blood pressure, those with declining blood pressure over time had less progression of subcortical atrophy, compared with those with increasing blood pressure.

Diffusion tensor imaging (DTI) of the basal ganglia and cerebellum may accurately diagnose Parkinson’s disease and other movement disorders, according to a study published online ahead of print May 14 in Movement Disorders. Investigators studied 72 subjects with DTI at 3 T. The technique distinguished between controls and patients with movement disorder with 92% sensitivity and 88% specificity. DTI also distinguished between controls and patients with parkinsonism (93% sensitivity, 91% specificity), Parkinson’s disease and atypical parkinsonism (90% sensitivity, 100% specificity), Parkinson’s disease and multiple system atrophy (94% sensitivity, 100% specificity), Parkinson’s disease and progressive supranuclear palsy (87% sensitivity, 100% specificity), multiple system atrophy and progressive supranuclear palsy (90% sensitivity, 100% specificity), and Parkinson’s disease and essential tremor (92% sensitivity, 87% specificity).

Heading a soccer ball may be associated with abnormal white matter microstructure and poor neurocognitive performance, according to research published online ahead of print June 11 in Radiology. Thirty-seven amateur soccer players answered a questionnaire about heading in the previous 12 months and lifetime history of concussions. Investigators performed diffusion-tensor MRI on the players and evaluated their cognitive function. The players had headed a median of 432 times during the previous year. Heading was associated with lower fractional anisotropy (FA) at three locations in temporo-occipital white matter with a threshold that varied according to location. Heading more than 1,800 times per year was associated with lower levels of FA and poorer memory scores. Concussion history and demographic features were not significantly associated with FA or cognitive performance.

Restless legs syndrome (RLS) may entail an increased risk of mortality, independent of known risk factors, according to a study published online ahead of print June 12 in Neurology. Researchers conducted a prospective cohort study of 18,425 American men without diabetes, arthritis, or renal failure. RLS was assessed using standardized questions. During eight years of follow-up, 2,765 deaths occurred. In an age-adjusted model, RLS was associated with a 39% increased risk of mortality. The association between RLS and mortality was slightly attenuated after further adjustment for BMI, lifestyle factors, chronic conditions, sleep duration, and other sleep-related disorders. When patients with major chronic conditions (eg, cancer, high blood pressure, cardiovascular disease, and other comorbidities) were excluded, the adjusted hazard ratio for RLS was 1.92.

Patients with stroke who are about to undergo surgery can safely continue to take aspirin or warfarin in many instances, according to a guideline published in the May 28 Neurology. Researchers systematically reviewed the literature to assess evidence about the periprocedural management of antithrombotic drugs in patients with ischemic cerebrovascular disease. Stroke patients undergoing dental procedures should routinely continue aspirin, according to the guideline. Stroke patients undergoing invasive ocular anesthesia, cataract surgery, dermatologic procedures, transrectal ultrasound–guided prostate biopsy, spinal or epidural procedures, and carpal tunnel surgery should probably continue aspirin. Stroke patients requiring warfarin should routinely continue it when undergoing dental procedures and probably continue it for dermatologic procedures. Some patients undergoing EMG, prostate procedures, inguinal herniorrhaphy, and endothermal ablation of the great saphenous vein should possibly continue warfarin.

Exposure to pesticides or solvents could be a risk factor for Parkinson’s disease, investigators concluded in the May 28 Neurology. Researchers performed a meta-analysis of prospective cohort and case-control studies that estimated the risk of Parkinson’s disease associated with exposure to pesticides or solvents. Parkinson’s disease was associated with farming, and the association between the disease and pesticides was highly significant in the studies in which Parkinson’s disease diagnosis was self-reported. In high-quality case-control studies, exposure to any pesticides, herbicides, and solvents increased the risk of Parkinson’s disease. Exposure to paraquat or maneb/mancozeb was associated with about a twofold increase in risk. Study quality was not a source of heterogeneity among prospective studies. In case-control studies, study quality was a source of heterogeneity in risk estimates for some exposures.

Atrial fibrillation may be associated with faster cognitive decline, according to a study published online ahead of print June 5 in Neurology. Researchers studied 5,150 men and women 65 or older who did not have atrial fibrillation or a history of stroke at baseline. Atrial fibrillation was identified by examining hospital discharge records and annual ECGs. A total of 552 patients (10.7%) developed incident atrial fibrillation during a mean seven years of follow-up. Mean Modified Mini-Mental State Examination (MMMSE) scores declined faster in patients with incident atrial fibrillation than in patients without atrial fibrillation. The predicted five-year decline in mean MMMSE score from age 80 to age 85 was −6.4 points for participants without atrial fibrillation and −10.3 points for participants with incident atrial fibrillation at age 80.

The level of interleukin 17F (IL-17F) in a patient with relapsing-remitting multiple sclerosis (MS) may not predict his or her response to treatment with interferon beta, according to research published online ahead of print June 3 in JAMA Neurology. Researchers analyzed serum samples from 239 randomly selected patients treated with interferon beta-1b (250 μg) for at least two years. Using clinical and MRI criteria, the investigators found that levels of IL-17F measured at baseline and month six did not correlate with lack of response to treatment after two years. Relapses and new lesions on MRI were not associated with pretreatment serum IL-17F levels. The results did not change when patients with neutralizing antibodies were excluded. Patients with levels of IL-17F higher than 200 pg/mL had poor response and clinical or radiologic activity.

Earlier treatment with thrombolytics may be associated with reduced mortality for patients with stroke, according to data published in the June 19 JAMA. Researchers analyzed data from 58,353 patients with acute ischemic stroke who were treated with t-PA within 4.5 hours of symptom onset in 1,395 hospitals. Patients’ median age was 72, 50.3% of patients were women, and median time to treatment was 144 minutes. A total of 5,142 in-hospital deaths occurred. Faster time to treatment, in 15-minute increments, was associated with reduced in-hospital mortality, reduced symptomatic intracranial hemorrhage, increased achievement of independent ambulation at discharge, and increased discharge to home. Patient factors most strongly associated with shorter time to treatment included greater stroke severity, arrival by ambulance, and arrival during regular hours.

High serum iron levels may be associated with a decreased risk of developing Parkinson’s disease, according to a study published June 4 in PLOS Medicine. Researchers investigated three polymorphisms in the genes HFE and TMPRSS6. For each polymorphism, they performed a meta-analysis of studies investigating the genetic effect on iron levels and a meta-analysis of studies investigating the genetic effect on the risk of Parkinson’s disease. Using three Mendelian randomization analyses, the investigators estimated the effect of iron on Parkinson’s disease for the three polymorphisms. Every 10 µg/dl increase in blood iron corresponded to a 3% reduction in the risk of Parkinson’s disease. Thus, increased blood iron levels may have a protective effect against Parkinson’s disease, but the underlying mechanism remains unclear, said the researchers.

Diabetes and dementia may have a bidirectional association, according to research published online ahead of print June 10 in JAMA Internal Medicine. Investigators examined 783 older adults with diabetes who were participating in a prospective population-based study. Subjects’ mean age was 74, and their baseline Modified Mini-Mental State Examination scores were 80 or higher. Approximately 47% of subjects were African American, and 47% were female. During the 12-year follow-up, 61 participants had a reported hypoglycemic event, and 148 developed dementia. Subjects who had a hypoglycemic event had a twofold increased risk for developing dementia, compared with those who did not have a hypoglycemic event. Subjects with diabetes who developed dementia had a greater risk for having a subsequent hypoglycemic event, compared with participants who did not develop dementia.

Cardiovascular biomarkers may help identify patients with subclinical cerebral injury, according to research published online ahead of print May 9 in Stroke. A total of 1,920 subjects received a brain MRI and had their levels of N-terminal brain natriuretic peptide (NT-proBNP) and cardiac troponin T (hs-cTnT) measured. Of the total group, 1,112 had a follow-up MRI between nine and 13 years later. Individuals with the highest NT-proBNP levels had significantly more silent brain infarcts and white matter lesions on the baseline MRI and more incident silent brain infarcts and white matter lesion progression on the follow-up MRI. Individuals with the highest hs-cTnT levels had more silent brain infarcts and white matter lesions on the initial MRI and more white matter lesion progression on the follow-up MRI.

Stroke symptoms or transient ischemic attack (TIA) may be strongly associated with incident cognitive impairment, researchers concluded in a study published online ahead of print June 19 in Neurology. The investigators studied 23,830 participants without cognitive impairment or history of stroke enrolled in the Reasons for Geographic and Racial Differences in Stroke Study. Subjects reported stroke symptoms and TIA every six months and were screened annually for cognitive impairment. Among Caucasians, the odds ratio for incident cognitive impairment was 2.08 for subjects reporting at least one stroke symptom or TIA, compared with those reporting no stroke symptom or TIA. Among African Americans, the odds ratio was 1.66 using the same modeling. The magnitude of impact was largest among participants with fewer traditional stroke risk factors.

—Erik Greb
Senior Associate Editor

In patients with arterial disease, low baseline diastolic blood pressure may correspond with increased progression of subcortical atrophy, researchers reported online ahead of print June 10 in JAMA Neurology. The association may not depend on subsequent change in blood pressure. Researchers measured blood pressure for 663 participants at baseline and at a mean of 3.9 years later. Change in brain parenchymal fraction, cortical gray matter fraction, and ventricular fraction were quantified as indicators of progression of global, cortical, and subcortical brain atrophy. Patients with lower baseline diastolic blood pressure or mean arterial pressure had more progression of subcortical atrophy. Of patients with higher baseline blood pressure, those with declining blood pressure over time had less progression of subcortical atrophy, compared with those with increasing blood pressure.

Diffusion tensor imaging (DTI) of the basal ganglia and cerebellum may accurately diagnose Parkinson’s disease and other movement disorders, according to a study published online ahead of print May 14 in Movement Disorders. Investigators studied 72 subjects with DTI at 3 T. The technique distinguished between controls and patients with movement disorder with 92% sensitivity and 88% specificity. DTI also distinguished between controls and patients with parkinsonism (93% sensitivity, 91% specificity), Parkinson’s disease and atypical parkinsonism (90% sensitivity, 100% specificity), Parkinson’s disease and multiple system atrophy (94% sensitivity, 100% specificity), Parkinson’s disease and progressive supranuclear palsy (87% sensitivity, 100% specificity), multiple system atrophy and progressive supranuclear palsy (90% sensitivity, 100% specificity), and Parkinson’s disease and essential tremor (92% sensitivity, 87% specificity).

Heading a soccer ball may be associated with abnormal white matter microstructure and poor neurocognitive performance, according to research published online ahead of print June 11 in Radiology. Thirty-seven amateur soccer players answered a questionnaire about heading in the previous 12 months and lifetime history of concussions. Investigators performed diffusion-tensor MRI on the players and evaluated their cognitive function. The players had headed a median of 432 times during the previous year. Heading was associated with lower fractional anisotropy (FA) at three locations in temporo-occipital white matter with a threshold that varied according to location. Heading more than 1,800 times per year was associated with lower levels of FA and poorer memory scores. Concussion history and demographic features were not significantly associated with FA or cognitive performance.

Restless legs syndrome (RLS) may entail an increased risk of mortality, independent of known risk factors, according to a study published online ahead of print June 12 in Neurology. Researchers conducted a prospective cohort study of 18,425 American men without diabetes, arthritis, or renal failure. RLS was assessed using standardized questions. During eight years of follow-up, 2,765 deaths occurred. In an age-adjusted model, RLS was associated with a 39% increased risk of mortality. The association between RLS and mortality was slightly attenuated after further adjustment for BMI, lifestyle factors, chronic conditions, sleep duration, and other sleep-related disorders. When patients with major chronic conditions (eg, cancer, high blood pressure, cardiovascular disease, and other comorbidities) were excluded, the adjusted hazard ratio for RLS was 1.92.

Patients with stroke who are about to undergo surgery can safely continue to take aspirin or warfarin in many instances, according to a guideline published in the May 28 Neurology. Researchers systematically reviewed the literature to assess evidence about the periprocedural management of antithrombotic drugs in patients with ischemic cerebrovascular disease. Stroke patients undergoing dental procedures should routinely continue aspirin, according to the guideline. Stroke patients undergoing invasive ocular anesthesia, cataract surgery, dermatologic procedures, transrectal ultrasound–guided prostate biopsy, spinal or epidural procedures, and carpal tunnel surgery should probably continue aspirin. Stroke patients requiring warfarin should routinely continue it when undergoing dental procedures and probably continue it for dermatologic procedures. Some patients undergoing EMG, prostate procedures, inguinal herniorrhaphy, and endothermal ablation of the great saphenous vein should possibly continue warfarin.

Exposure to pesticides or solvents could be a risk factor for Parkinson’s disease, investigators concluded in the May 28 Neurology. Researchers performed a meta-analysis of prospective cohort and case-control studies that estimated the risk of Parkinson’s disease associated with exposure to pesticides or solvents. Parkinson’s disease was associated with farming, and the association between the disease and pesticides was highly significant in the studies in which Parkinson’s disease diagnosis was self-reported. In high-quality case-control studies, exposure to any pesticides, herbicides, and solvents increased the risk of Parkinson’s disease. Exposure to paraquat or maneb/mancozeb was associated with about a twofold increase in risk. Study quality was not a source of heterogeneity among prospective studies. In case-control studies, study quality was a source of heterogeneity in risk estimates for some exposures.

Atrial fibrillation may be associated with faster cognitive decline, according to a study published online ahead of print June 5 in Neurology. Researchers studied 5,150 men and women 65 or older who did not have atrial fibrillation or a history of stroke at baseline. Atrial fibrillation was identified by examining hospital discharge records and annual ECGs. A total of 552 patients (10.7%) developed incident atrial fibrillation during a mean seven years of follow-up. Mean Modified Mini-Mental State Examination (MMMSE) scores declined faster in patients with incident atrial fibrillation than in patients without atrial fibrillation. The predicted five-year decline in mean MMMSE score from age 80 to age 85 was −6.4 points for participants without atrial fibrillation and −10.3 points for participants with incident atrial fibrillation at age 80.

The level of interleukin 17F (IL-17F) in a patient with relapsing-remitting multiple sclerosis (MS) may not predict his or her response to treatment with interferon beta, according to research published online ahead of print June 3 in JAMA Neurology. Researchers analyzed serum samples from 239 randomly selected patients treated with interferon beta-1b (250 μg) for at least two years. Using clinical and MRI criteria, the investigators found that levels of IL-17F measured at baseline and month six did not correlate with lack of response to treatment after two years. Relapses and new lesions on MRI were not associated with pretreatment serum IL-17F levels. The results did not change when patients with neutralizing antibodies were excluded. Patients with levels of IL-17F higher than 200 pg/mL had poor response and clinical or radiologic activity.

Earlier treatment with thrombolytics may be associated with reduced mortality for patients with stroke, according to data published in the June 19 JAMA. Researchers analyzed data from 58,353 patients with acute ischemic stroke who were treated with t-PA within 4.5 hours of symptom onset in 1,395 hospitals. Patients’ median age was 72, 50.3% of patients were women, and median time to treatment was 144 minutes. A total of 5,142 in-hospital deaths occurred. Faster time to treatment, in 15-minute increments, was associated with reduced in-hospital mortality, reduced symptomatic intracranial hemorrhage, increased achievement of independent ambulation at discharge, and increased discharge to home. Patient factors most strongly associated with shorter time to treatment included greater stroke severity, arrival by ambulance, and arrival during regular hours.

High serum iron levels may be associated with a decreased risk of developing Parkinson’s disease, according to a study published June 4 in PLOS Medicine. Researchers investigated three polymorphisms in the genes HFE and TMPRSS6. For each polymorphism, they performed a meta-analysis of studies investigating the genetic effect on iron levels and a meta-analysis of studies investigating the genetic effect on the risk of Parkinson’s disease. Using three Mendelian randomization analyses, the investigators estimated the effect of iron on Parkinson’s disease for the three polymorphisms. Every 10 µg/dl increase in blood iron corresponded to a 3% reduction in the risk of Parkinson’s disease. Thus, increased blood iron levels may have a protective effect against Parkinson’s disease, but the underlying mechanism remains unclear, said the researchers.

Diabetes and dementia may have a bidirectional association, according to research published online ahead of print June 10 in JAMA Internal Medicine. Investigators examined 783 older adults with diabetes who were participating in a prospective population-based study. Subjects’ mean age was 74, and their baseline Modified Mini-Mental State Examination scores were 80 or higher. Approximately 47% of subjects were African American, and 47% were female. During the 12-year follow-up, 61 participants had a reported hypoglycemic event, and 148 developed dementia. Subjects who had a hypoglycemic event had a twofold increased risk for developing dementia, compared with those who did not have a hypoglycemic event. Subjects with diabetes who developed dementia had a greater risk for having a subsequent hypoglycemic event, compared with participants who did not develop dementia.

Cardiovascular biomarkers may help identify patients with subclinical cerebral injury, according to research published online ahead of print May 9 in Stroke. A total of 1,920 subjects received a brain MRI and had their levels of N-terminal brain natriuretic peptide (NT-proBNP) and cardiac troponin T (hs-cTnT) measured. Of the total group, 1,112 had a follow-up MRI between nine and 13 years later. Individuals with the highest NT-proBNP levels had significantly more silent brain infarcts and white matter lesions on the baseline MRI and more incident silent brain infarcts and white matter lesion progression on the follow-up MRI. Individuals with the highest hs-cTnT levels had more silent brain infarcts and white matter lesions on the initial MRI and more white matter lesion progression on the follow-up MRI.

Stroke symptoms or transient ischemic attack (TIA) may be strongly associated with incident cognitive impairment, researchers concluded in a study published online ahead of print June 19 in Neurology. The investigators studied 23,830 participants without cognitive impairment or history of stroke enrolled in the Reasons for Geographic and Racial Differences in Stroke Study. Subjects reported stroke symptoms and TIA every six months and were screened annually for cognitive impairment. Among Caucasians, the odds ratio for incident cognitive impairment was 2.08 for subjects reporting at least one stroke symptom or TIA, compared with those reporting no stroke symptom or TIA. Among African Americans, the odds ratio was 1.66 using the same modeling. The magnitude of impact was largest among participants with fewer traditional stroke risk factors.

—Erik Greb
Senior Associate Editor