Separate prediction of intracerebral hemorrhage and ischemic stroke

OBJECTIVES

To develop and validate 10-year cumulative incidence functions of intracerebral hemorrhage (ICH) and ischemic stroke (IS).

METHODS

We used data on 27,493 participants from 3 population-based cohort studies: the Atherosclerosis Risk in Communities Study, median age 54 years, 45% male, median follow-up 20.7 years; the Rotterdam Study, median age 68 years, 38% male, median follow-up 14.3 years; and the Cardiovascular Health Study, median age 71 years, 41% male, median follow-up 12.8 years. Among these participants, 325 ICH events, 2,559 IS events, and 9,909 nonstroke deaths occurred. We developed 10-year cumulative incidence functions for ICH and IS using stratified Cox regression and competing risks analysis. Basic models including only established nonlaboratory risk factors were extended with diastolic blood pressure, total cholesterol/high-density lipoprotein cholesterol ratio, body mass index, waist-to-hip ratio, and glomerular filtration rate. The cumulative incidence functions' performances were cross-validated in each cohort separately by Harrell C-statistic and calibration plots.

RESULTS

High total cholesterol/high-density lipoprotein cholesterol ratio decreased the ICH rates but increased IS rates (p for difference across stroke types <0.001). For both the ICH and IS models, C statistics increased more by model extension in the Atherosclerosis Risk in Communities and Cardiovascular Health Study cohorts. Improvements in C statistics were reproduced by cross-validation. Models were well calibrated in all cohorts. Correlations between 10-year ICH and IS risks were moderate in each cohort.

CONCLUSIONS

We developed and cross-validated cumulative incidence functions for separate prediction of 10-year ICH and IS risk. These functions can be useful to further specify an individual's stroke risk.

Differences in end-of-life care in the ICU across patients cared for by medicine, surgery, neurology, and neurosurgery physicians

BACKGROUND

Some of the challenges in the delivery of high-quality end-of-life care in the ICU include the variability in the characteristics of patients with certain illnesses and the practice of critical care by different specialties.

METHODS

We examined whether ICU attending specialty was associated with quality of end-of-life care by using data from a clustered randomized trial of 14 hospitals. Patients died in the ICU or within 30 h of transfer and were categorized by specialty of the attending physician at time of death (medicine, surgery, neurology, or neurosurgery). Outcomes included family ratings of satisfaction, family and nurse ratings of quality of dying, and documentation of palliative care in medical records. Associations were tested using multipredictor regression models adjusted for hospital site and for patient, family, or nurse characteristics.

RESULTS

Of 3,124 patients, the majority were cared for by an attending physician specializing in medicine (78%), with fewer from surgery (12%), neurology (3%), and neurosurgery (6%). Family satisfaction did not vary by attending specialty. Patients with neurology or neurosurgery attending physicians had higher family and nurse ratings of quality of dying than patients of attending physicians specializing in medicine (P &lt; .05). Patients with surgery attending physicians had lower nurse ratings of quality of dying than patients with medicine attending physicians (P &lt; .05). Chart documentation of indicators of palliative care differed by attending specialty.

CONCLUSIONS

Patients cared for by neurology and neurosurgery attending physicians have higher family and nurse ratings of quality of dying than patients cared for by medicine attending physicians and have a different pattern of indicators of palliative care. Patients with surgery attending physicians had fewer documented indicators of palliative care. These findings may provide insights into potential ways to improve the quality of dying for all patients.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00685893; URL: www.clinicaltrials.gov.

Rare coding variation in paraoxonase-1 is associated with ischemic stroke in the NHLBI Exome Sequencing Project

HDL-associated paraoxonase-1 (PON1) is an enzyme whose activity is associated with cerebrovascular disease. Common PON1 genetic variants have not been consistently associated with cerebrovascular disease. Rare coding variation that likely alters PON1 enzyme function may be more strongly associated with stroke. The National Heart, Lung, and Blood Institute Exome Sequencing Project sequenced the coding regions (exomes) of the genome for heart, lung, and blood-related phenotypes (including ischemic stroke). In this sample of 4,204 unrelated participants, 496 had verified, noncardioembolic ischemic stroke. After filtering, 28 nonsynonymous PON1 variants were identified. Analysis with the sequence kernel association test, adjusted for covariates, identified significant associations between PON1 variants and ischemic stroke (P = 3.01 × 10(-3)). Stratified analyses demonstrated a stronger association of PON1 variants with ischemic stroke in African ancestry (AA) participants (P = 5.03 × 10(-3)). Ethnic differences in the association between PON1 variants with stroke could be due to the effects of PON1Val109Ile (overall P = 7.88 × 10(-3); AA P = 6.52 × 10(-4)), found at higher frequency in AA participants (1.16% vs. 0.02%) and whose protein is less stable than the common allele. In summary, rare genetic variation in PON1 was associated with ischemic stroke, with stronger associations identified in those of AA. Increased focus on PON1 enzyme function and its role in cerebrovascular disease is warranted.

Predicting stroke through genetic risk functions: the CHARGE Risk Score Project

BACKGROUND AND PURPOSE

Beyond the Framingham Stroke Risk Score, prediction of future stroke may improve with a genetic risk score (GRS) based on single-nucleotide polymorphisms associated with stroke and its risk factors.

METHODS

The study includes 4 population-based cohorts with 2047 first incident strokes from 22,720 initially stroke-free European origin participants aged ≥55 years, who were followed for up to 20 years. GRSs were constructed with 324 single-nucleotide polymorphisms implicated in stroke and 9 risk factors. The association of the GRS to first incident stroke was tested using Cox regression; the GRS predictive properties were assessed with area under the curve statistics comparing the GRS with age and sex, Framingham Stroke Risk Score models, and reclassification statistics. These analyses were performed per cohort and in a meta-analysis of pooled data. Replication was sought in a case-control study of ischemic stroke.

RESULTS

In the meta-analysis, adding the GRS to the Framingham Stroke Risk Score, age and sex model resulted in a significant improvement in discrimination (all stroke: Δjoint area under the curve=0.016, P=2.3×10(-6); ischemic stroke: Δjoint area under the curve=0.021, P=3.7×10(-7)), although the overall area under the curve remained low. In all the studies, there was a highly significantly improved net reclassification index (P<10(-4)).

CONCLUSIONS

The single-nucleotide polymorphisms associated with stroke and its risk factors result only in a small improvement in prediction of future stroke compared with the classical epidemiological risk factors for stroke.

Effect of prehospital induction of mild hypothermia on survival and neurological status among adults with cardiac arrest: a randomized clinical trial

IMPORTANCE

Hospital cooling improves outcome after cardiac arrest, but prehospital cooling immediately after return of spontaneous circulation may result in better outcomes.

OBJECTIVE

To determine whether prehospital cooling improves outcomes after resuscitation from cardiac arrest in patients with ventricular fibrillation (VF) and without VF.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial that assigned adults with prehospital cardiac arrest to standard care with or without prehospital cooling, accomplished by infusing up to 2 L of 4°C normal saline as soon as possible following return of spontaneous circulation. Adults in King County, Washington, with prehospital cardiac arrest and resuscitated by paramedics were eligible and 1359 patients (583 with VF and 776 without VF) were randomized between December 15, 2007, and December 7, 2012. Patient follow-up was completed by May 1, 2013. Nearly all of the patients resuscitated from VF and admitted to the hospital received hospital cooling regardless of their randomization.

MAIN OUTCOMES AND MEASURES

The primary outcomes were survival to hospital discharge and neurological status at discharge.

RESULTS

The intervention decreased mean core temperature by 1.20°C (95% CI, -1.33°C to -1.07°C) in patients with VF and by 1.30°C (95% CI, -1.40°C to -1.20°C) in patients without VF by hospital arrival and reduced the time to achieve a temperature of less than 34°C by about 1 hour compared with the control group. However, survival to hospital discharge was similar among the intervention and control groups among patients with VF (62.7% [95% CI, 57.0%-68.0%] vs 64.3% [95% CI, 58.6%-69.5%], respectively; P = .69) and among patients without VF (19.2% [95% CI, 15.6%-23.4%] vs 16.3% [95% CI, 12.9%-20.4%], respectively; P = .30). The intervention was also not associated with improved neurological status of full recovery or mild impairment at discharge for either patients with VF (57.5% [95% CI, 51.8%-63.1%] of cases had full recovery or mild impairment vs 61.9% [95% CI, 56.2%-67.2%] of controls; P = .69) or those without VF (14.4% [95% CI, 11.3%-18.2%] of cases vs 13.4% [95% CI,10.4%-17.2%] of controls; P = .30). Overall, the intervention group experienced rearrest in the field more than the control group (26% [95% CI, 22%-29%] vs 21% [95% CI, 18%-24%], respectively; P = .008), as well as increased diuretic use and pulmonary edema on first chest x-ray, which resolved within 24 hours after admission.

CONCLUSION AND RELEVANCE

Although use of prehospital cooling reduced core temperature by hospital arrival and reduced the time to reach a temperature of 34°C, it did not improve survival or neurological status among patients resuscitated from prehospital VF or those without VF.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00391469.

Blood pressure variability and the risk of all-cause mortality, incident myocardial infarction, and incident stroke in the cardiovascular health study

BACKGROUND

Recent reports have linked variability in visit-to-visit systolic blood pressure (SBP) to risk of mortality and stroke, independent of the effect of mean SBP level. This study aimed to evaluate whether variability in SBP is associated with all-cause mortality, incident myocardial infarction (MI), and incident stroke, independent of mean SBP or trends in SBP levels over time.

METHODS

The Cardiovascular Health Study is a longitudinal cohort study of vascular risk factors and disease in the elderly. Participants who attended their first 5 annual clinic visits and experienced no event before the 5th visit were eligible (n = 3,852). Primary analyses were restricted to participants not using antihypertensive medications throughout the first 5 clinic visits (n = 1,642). Intraindividual SBP variables were defined using each participant's 5-visit blood pressure measures. Cox proportional hazards models estimated adjusted hazard ratios (HRs) per SD increase in intraindividual SBP variability, adjusted for intraindividual SBP mean and change over time.

RESULTS

Over a mean follow-up of 9.9 years, there were 844 deaths, 203 MIs, and 195 strokes. Intraindividual SBP variability was significantly associated with increased risk of mortality (HR = 1.13; 95% confidence interval (CI) = 1.05-1.21) and of incident MI (HR = 1.20; 95%CI = 1.06-1.36), independent of the effect from adjustment factors. Intraindividual SBP variability was not associated with risk of stroke (HR = 1.03; 95% CI = 0.89-1.21).

CONCLUSIONS

Long-term visit-to-visit SBP variability was independently associated with a higher risk of subsequent mortality and MI but not stroke. More research is needed to determine the relationship of BP variability with cardiovascular risk and the clinical implications.

Parkinson's disease and history of outdoor occupation

BACKGROUND

Human and animal studies, albeit not fully consistent, suggest that vitamin D may reduce risk of Parkinson's disease (PD). Ultraviolet radiation converts vitamin D precursor to the active form. This study examined the hypothesis that working outdoors is associated with a decreased risk of PD.

METHODS

PD cases were enrolled from Group Health Cooperative, a health maintenance organization in the Puget Sound region in western Washington State, and the University of Washington Neurology Clinic in Seattle. Participants included 447 non-Hispanic Caucasian newly diagnosed PD cases diagnosed between 1992 and 2008 and 578 unrelated neurologically normal controls enrolled in Group Health Cooperative, frequency matched by race/ethnicity, age and gender. Subjects' amount of outdoor work was estimated from self-reported occupational histories. Jobs were categorized by degree of time spent working outdoors. A ten-year lag interval was included to account for disease latency. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression, with adjustment for age, gender, and smoking.

RESULTS

Outdoor work was inversely associated with risk of PD (outdoor only compared to indoor only): OR = 0.74, 95% CI 0.44-1.25. However, there was no trend in relation to portion of the workday spent laboring outdoors and PD risk.

CONCLUSION

Occupational sunlight exposure and other correlates of outdoor work is not likely to have a substantial role in the etiology of PD.

Early diagnosis and treatment of obstructive sleep apnea after stroke: Are we neglecting a modifiable stroke risk factor?

Sleep-disordered breathing is an increasingly recognized disorder that is particularly prevalent among stroke patients. Obstructive sleep apnea, a form of sleep-disordered breathing, is associated with multiple major stroke risk factors but is also an independent risk factor for stroke. In addition, untreated sleep apnea is associated with poor functional outcome after stroke. Sleep apnea is amenable to treatment and should be considered a modifiable stroke risk factor, though long-term compliance remains a major barrier. A better understanding of the relationship between sleep apnea and stroke may prompt providers to pursue the early diagnosis and treatment of underlying sleep-disordered breathing to both improve the chance of recovery from stroke in the short term and to reduce the risk of recurrent stroke in the long term.

Atrial fibrillation and cognitive decline: a longitudinal cohort study

OBJECTIVE

We sought to determine whether in the absence of clinical stroke, people with atrial fibrillation experience faster cognitive decline than people without atrial fibrillation.

METHODS

We conducted a longitudinal analysis in the Cardiovascular Health Study, a community-based study of 5,888 men and women aged 65 years and older, enrolled in 1989/1990 or 1992/1993. Participants did not have atrial fibrillation or a history of stroke at baseline. Participants were censored when they experienced incident clinical stroke. Incident atrial fibrillation was identified by hospital discharge diagnosis codes and annual study ECGs. The main outcome was rate of decline in mean scores on the 100-point Modified Mini-Mental State Examination (3MSE), administered annually up to 9 times.

RESULTS

Analyses included 5,150 participants, of whom 552 (10.7%) developed incident atrial fibrillation during a mean of 7 years of follow-up. Mean 3MSE scores declined faster after incident atrial fibrillation compared with no prior atrial fibrillation. For example, the predicted 5-year decline in mean 3MSE score from age 80 to age 85 was -6.4 points (95% confidence interval [CI]: -7.0, -5.9) for participants without a history of atrial fibrillation, but was -10.3 points (95% CI: -11.8, -8.9) for participants experiencing incident atrial fibrillation at age 80, a 5-year difference of -3.9 points (95% CI: -5.3, -2.5).

CONCLUSIONS

In the absence of clinical stroke, people with incident atrial fibrillation are likely to reach thresholds of cognitive impairment or dementia at earlier ages than people with no history of atrial fibrillation.

Nicotine from edible Solanaceae and risk of Parkinson disease

OBJECTIVE

To test whether risk of Parkinson disease (PD) is associated with consumption of nicotine-containing edibles from the same botanical family as tobacco, Solanaceae, including peppers, tomatoes, and potatoes.

METHODS

In a population-based study with 490 newly diagnosed idiopathic PD cases diagnosed during 1992-2008 at the University of Washington Neurology Clinic or Group Health Cooperative in western Washington State and 644 unrelated, neurologically normal controls, we examined whether PD was associated with self-reported typical frequency of consumption of peppers, tomatoes, tomato juice, and potatoes during adulthood, while adjusting for consumption of other vegetables, age, sex, race/ethnicity, tobacco use, and caffeine.

RESULTS

PD was inversely associated with consumption of all edible Solanaceae combined (relative risk [RR] = 0.81, 95% confidence interval [CI] = 0.65-1.01 per time per day), but not consumption of all other vegetables combined (RR = 1.00, 95% CI = 0.92-1.10). The trend strengthened when we weighted edible Solanaceae by nicotine concentration (ptrend = 0.004). An inverse association was also evident for peppers specifically (ptrend = 0.005). The potentially protective effect of edible Solanaceae largely occurred in men and women who had never used tobacco or who had smoked cigarettes < 10 years.

INTERPRETATION

Dietary nicotine or other constituents of tobacco and peppers may reduce PD risk. However, confirmation and extension of these findings are needed to strengthen causal inferences that could suggest possible dietary or pharmaceutical interventions for PD prevention.

Exploring psychosocial pathways between neighbourhood characteristics and stroke in older adults: the cardiovascular health study

OBJECTIVES

to investigate whether psychosocial pathways mediate the association between neighbourhood socioeconomic disadvantage and stroke.

METHODS

prospective cohort study with a follow-up of 11.5 years.

SETTING

the Cardiovascular Health Study, a longitudinal population-based cohort study of older adults ≥65 years.

MEASUREMENTS

the primary outcome was adjudicated incident ischaemic stroke. Neighbourhood socioeconomic status (NSES) was measured using a composite of six census-tract variables. Psychosocial factors were assessed with standard measures for depression, social support and social networks.

RESULTS

of the 3,834 white participants with no prior stroke, 548 had an incident ischaemic stroke over the 11.5-year follow-up. Among whites, the incident stroke hazard ratio (HR) associated with living in the lowest relative to highest NSES quartile was 1.32 (95% CI = 1.01-1.73), in models adjusted for individual SES. Additional adjustment for psychosocial factors had a minimal effect on hazard of incident stroke (HR = 1.31, CI = 1.00-1.71). Associations between NSES and stroke incidence were not found among African-Americans (n = 785) in either partially or fully adjusted models.

CONCLUSIONS

psychosocial factors played a minimal role in mediating the effect of NSES on stroke incidence among white older adults.

Genotype and age at Parkinson disease diagnosis

Parkinson disease (PD) is a degenerative movement disorder that results from the destruction of dopaminergic neurons in the midbrain substantia nigra. Both genetic and environmental factors contribute to PD risk, and likely to age at diagnosis. Among 258 newly diagnosed non-Hispanic Caucasian cases from Group Health Cooperative in western Washington State, we assessed whether diagnosis age was associated with 1,327 single nucleotide polymorphisms in genes related to central nervous system function, oxidative stress, inflammation or metal transport. We conducted linear regression to assess the age difference per variant allele while adjusting for sex and smoking. Of the polymorphisms associated with PD diagnosis age (ptrend<0.05), three demonstrated similar associations among 64 PD cases from the University of Washington Neurology Clinic, were not similarly associated (pinteraction<0.05) with age in general among 436 unrelated non-Hispanic Caucasian controls from the source population, and were predicted to be functional according to a public National Institute of Environmental Health Sciences polymorphism database. The most robust association was for rs10889162, a polymorphism in a predicted transcription factor binding site -582 bp from CYP2J2 arachidonic acid epoxygenase. Each variant allele was associated with 5.04 years older diagnosis age (95% confidence interval 2.28-7.80, p=0.0003). This association did not vary by sex or smoking history. Polymorphisms in predicted microRNA binding sites in GSTM5 and SLC11A2 were also associated with >2-year differences in diagnosis age. These results await confirmation in other series of incident cases, but suggest that selected genes and environmental exposures may influence PD diagnosis age.

Abstract WP377: Outcome After Stroke - “Good” Or “Poor”?

Background: The modified Rankin Scale (mRS) is a commonly used instrument to measure outcome in stroke research and is often dichotomized into good and poor outcome. Quality of life (QoL) is likely affected by factors besides level of disability. The goal of this study was to assess the correlation between the mRS and a more patient-centered QOL measure, the European QoL visual analog scale (EQVAS).

Methods: The Medic One Stroke Study reviewed pre-hospital and hospital records from 11 acute care hospitals in the Seattle area from June 2000-January 2003. Subjects with a final hospital diagnosis of stroke were telephoned 3-4 months after stroke onset and both mRS (0-6, with 0 the best) and EQ VAS (0-100 with 100 best) were assessed.

Results: We identified 574 patients with stroke: 420 ischemic stroke (IS), 121 intraparenchymal hemorrhage (IPH) and 33 subarachnoid hemorrhage (SAH). At three months after discharge, the proportion with mRS of ≤ 3 varied significantly with stroke type: 50% IS, 20% IPH, and 27% SAH (p<0.001). Similarly, good quality of life, defined as EuroQoL ≥ 75, occurred in 48% IS, 25% IPH, and 27% SAH (p<0.001). Spearman’s rho showed a strong correlation of 0.89 (p<0.001) between mRS and EuroQoL. Likelihood of good QoL progressively decreased with increasing mRS (82%, 58%, 33%, 31%, 21%, 11% for mRS 0-5, respectively, p<0.001), yet a number of patients with high mRS (4,5) still reported good QoL (16/102 = 16%). Among patients with low mRS (0,1), 32% did not achieve good QoL.

Conclusion: Following stroke, QoL decreases with increasing mRS, but exceptions exist with good QoL despite high mRS scores. In the endeavor to advance patient-centeredness as a core component of quality health care, factors other than disability need further exploration, both by researchers doing clinical trials as well as by physicians making treatment recommendations.

Abstract WMP64: Prehospital Triage To Comprehensive Stroke Centers: GCS Identifies Patients At Increased Risk For Death, ICH, Or SAH

INTRODUCTION: Regionalization of stroke care is occurring nationwide, but evidence-based criteria for prehospital triage to comprehensive stroke centers are lacking. We assessed the hypothesis that a prehospital clinical decision rule can identify a group of patients more likely to require comprehensive stroke services--those with an increased risk of in-hospital mortality, ICH, or SAH.

METHODS: This study represents a retrospective cohort of patients seen by an urban EMS system from 2000-2003. Subjects were included if they had either a prehospital diagnosis of “stroke/TIA” or a prehospital diagnosis of “decreased level of consciousness” or “headache” and signs and symptoms suggestive of a cerebrovascular event. The primary outcome was a composite of in-hospital mortality, ICH, or SAH. Multivariate logistic regression was used to derive a clinical prediction rule.

RESULTS: In 1682 subjects, the discharge diagnoses included TIA (n = 282, 17%), ischemic stroke (n = 433, 26%), ICH (n = 102, 6%), and SAH (n = 30, 2%). There were 221 patients (13%) who experienced the primary outcome: 67 (4%) with non-fatal ICH or SAH and 154 (9%) who died. Using GCS score alone, the area under ROC curve was 0.72, and GCS ≤ 10 resulted in a sensitivity of 0.48 (95%CI 0.42, 0.55) and specificity of 0.88 (95%CI 0.87, 0.90). A six-point prehospital stroke triage score (PSTS) was also derived: nausea/vomiting (1 point), systolic BP ≥ 175 (1 point), GCS 7-10 (2 points) and GCS 3-6 (4 points). The area under ROC curve for the PSTS was 0.74. Test characteristics for PSTS and GCS were similar (Table).

CONCLUSION: GCS alone performed similarly to a six-point clinical decision rule for the prehospital identification of patients at increased risk of death, ICH or SAH. GCS has potential utility as a criterion for the prehospital triage to comprehensive stroke centers.

Amino terminal pro-B-type natriuretic peptide, secondary stroke prevention, and choice of antithrombotic therapy

BACKGROUND AND PURPOSE

Because of its association with atrial fibrillation and heart failure, we hypothesized that amino terminal pro-B-type natriuretic peptide (NT-proBNP) would identify a subgroup of patients from the Warfarin-Aspirin Recurrent Stroke Study, diagnosed with inferred noncardioembolic ischemic strokes, where anticoagulation would be more effective than antiplatelet agents in reducing risk of subsequent events.

METHODS

NT-proBNP was measured in stored serum collected at baseline from participants enrolled in Warfarin-Aspirin Recurrent Stroke Study, a previously reported randomized trial. Relative effectiveness of warfarin and aspirin in preventing recurrent ischemic stroke or death over 2 years was compared based on NT-proBNP concentrations.

RESULTS

About 95% of 1028 patients with assays had NT-proBNP below 750 pg/mL, and among them, no evidence for treatment effect modification was evident. For 49 patients with NT-proBNP >750 pg/mL, the 2-year rate of events per 100 person-years was 45.9 for the aspirin group and 16.6 for the warfarin group, whereas for 979 patients with NT-proBNP ≤750 pg/mL, rates were similar for both treatments. For those with NT-proBNP >750 pg/mL, the hazard ratio was 0.30 (95% confidence interval: 0.12-0.84; P=0.021) significantly favoring warfarin over aspirin. A formal test for interaction of NT-proBNP with treatment was significant (P=0.01).

CONCLUSIONS

For secondary stroke prevention, elevated NT-proBNP concentrations may identify a subgroup of ischemic stroke patients without known atrial fibrillation, about 5% based on the current study, who may benefit more from anticoagulants than antiplatelet agents. Clinical Trial Registration- This trial was not registered because enrollment began before 2005.

Neighborhood socioeconomic disadvantage and mortality after stroke

OBJECTIVE

Residence in a socioeconomically disadvantaged community is associated with mortality, but the mechanisms are not well understood. We examined whether socioeconomic features of the residential neighborhood contribute to poststroke mortality and whether neighborhood influences are mediated by traditional behavioral and biologic risk factors.

METHODS

We used data from the Cardiovascular Health Study, a multicenter, population-based, longitudinal study of adults ≥65 years. Residential neighborhood disadvantage was measured using neighborhood socioeconomic status (NSES), a composite of 6 census tract variables representing income, education, employment, and wealth. Multilevel Cox proportional hazard models were constructed to determine the association of NSES to mortality after an incident stroke, adjusted for sociodemographic characteristics, stroke type, and behavioral and biologic risk factors.

RESULTS

Among the 3,834 participants with no prior stroke at baseline, 806 had a stroke over a mean 11.5 years of follow-up, with 168 (20%) deaths 30 days after stroke and 276 (34%) deaths at 1 year. In models adjusted for demographic characteristics, stroke type, and behavioral and biologic risk factors, mortality hazard 1 year after stroke was significantly higher among residents of neighborhoods with the lowest NSES than those in the highest NSES neighborhoods (hazard ratio 1.77, 95% confidence interval 1.17-2.68).

CONCLUSION

Living in a socioeconomically disadvantaged neighborhood is associated with higher mortality hazard at 1 year following an incident stroke. Further work is needed to understand the structural and social characteristics of neighborhoods that may contribute to mortality in the year after a stroke and the pathways through which these characteristics operate.

Genetic risk factors for ischaemic stroke and its subtypes (the METASTROKE collaboration): a meta-analysis of genome-wide association studies

BACKGROUND

Various genome-wide association studies (GWAS) have been done in ischaemic stroke, identifying a few loci associated with the disease, but sample sizes have been 3500 cases or less. We established the METASTROKE collaboration with the aim of validating associations from previous GWAS and identifying novel genetic associations through meta-analysis of GWAS datasets for ischaemic stroke and its subtypes.

METHODS

We meta-analysed data from 15 ischaemic stroke cohorts with a total of 12 389 individuals with ischaemic stroke and 62 004 controls, all of European ancestry. For the associations reaching genome-wide significance in METASTROKE, we did a further analysis, conditioning on the lead single nucleotide polymorphism in every associated region. Replication of novel suggestive signals was done in 13 347 cases and 29 083 controls.

FINDINGS

We verified previous associations for cardioembolic stroke near PITX2 (p=2·8×10(-16)) and ZFHX3 (p=2·28×10(-8)), and for large-vessel stroke at a 9p21 locus (p=3·32×10(-5)) and HDAC9 (p=2·03×10(-12)). Additionally, we verified that all associations were subtype specific. Conditional analysis in the three regions for which the associations reached genome-wide significance (PITX2, ZFHX3, and HDAC9) indicated that all the signal in each region could be attributed to one risk haplotype. We also identified 12 potentially novel loci at p<5×10(-6). However, we were unable to replicate any of these novel associations in the replication cohort.

INTERPRETATION

Our results show that, although genetic variants can be detected in patients with ischaemic stroke when compared with controls, all associations we were able to confirm are specific to a stroke subtype. This finding has two implications. First, to maximise success of genetic studies in ischaemic stroke, detailed stroke subtyping is required. Second, different genetic pathophysiological mechanisms seem to be associated with different stroke subtypes.

FUNDING

Wellcome Trust, UK Medical Research Council (MRC), Australian National and Medical Health Research Council, National Institutes of Health (NIH) including National Heart, Lung and Blood Institute (NHLBI), the National Institute on Aging (NIA), the National Human Genome Research Institute (NHGRI), and the National Institute of Neurological Disorders and Stroke (NINDS).

Gender differences in tea, coffee, and cognitive decline in the elderly: the Cardiovascular Health Study

Although caffeine can enhance cognitive function acutely, long-term effects of consumption of caffeine-containing beverages such as tea and coffee are uncertain. Data on 4,809 participants aged 65 and older from the Cardiovascular Health Study (CHS) were used to examine the relationship of consumption of tea and coffee, assessed by food frequency questionnaire, on change in cognitive function by gender. Cognitive performance was assessed using serial Modified Mini-Mental State (3MS) examinations, which were administered annually up to 9 times. Linear mixed models were used to estimate rates of change in standard 3MS scores and scores modeled using item response theory (IRT). Models were adjusted for age, education, smoking status, clinic site, diabetes, hypertension, stroke, coronary heart disease, depression score, and APOE genotype. Over the median 7.9 years of follow-up, participants who did not consume tea or coffee declined annually an average of 1.30 points (women) and 1.11 points (men) on standard 3MS scores. In fully adjusted models using either standard or IRT 3MS scores, we found modestly reduced rates of cognitive decline for some, but not all, levels of coffee and tea consumption for women, with no consistent effect for men. Caffeine consumption was also associated with attenuation in cognitive decline in women. Dose-response relationships were not linear. These longitudinal analyses suggest a somewhat attenuated rate of cognitive decline among tea and coffee consumers compared to non-consumers in women but not in men. Whether this association is causal or due to unmeasured confounding requires further study.

Acute kidney injury is associated with increased hospital mortality after stroke

BACKGROUND

Acute kidney injury (AKI) is common and is associated with poor clinical outcomes. Information about the incidence of AKI and its effect on stroke outcomes is limited.

METHODS

Data were analyzed from a registry of subjects with ischemic stroke and intracerebral hemorrhage (ICH) hospitalized at a single academic medical center. Admission creatinine was considered to be the baseline. AKI was defined as a creatinine increase during hospitalization of 0.3 mg/dL or a percentage increase of at least 50% from baseline. Multivariate logistic regression models were created for both stroke types, with hospital mortality as the outcome. Covariates included gender, race, age, admission creatinine, National Institutes of Health Stroke Scale score at admission, the performance of a contrast-enhanced computed tomographic scan of the head and neck, and medical comorbidities.

RESULTS

There were 528 cases of ischemic stroke with 70 deaths (13%), and 829 cases of ICH with 268 deaths (32%). The mean age was 64 years; 56% of patients were men and 71% were white. AKI complicated 14% of ischemic stroke and 21% of ICH hospitalizations. In multivariate analysis stratified by stroke type, AKI was associated with increased hospital mortality from ischemic stroke (odds ratio [OR] 3.08; 95% confidence interval [CI] 1.49-6.35) but not ICH (OR 0.82; 95% CI 0.50-1.35), except for those surviving at least 2 days (OR 2.11; 95% CI 1.18-3.77).

CONCLUSIONS

AKI occurs frequently after stroke and is associated with increased hospital mortality. Additional studies are needed to establish if the association is causal and if measures to prevent AKI would result in decreased mortality.

Risk of intraparenchymal hemorrhage with magnetic resonance imaging-defined leukoaraiosis and brain infarcts

OBJECTIVE

To determine whether the burden of leukoaraiosis and the number of brain infarcts, defined by magnetic resonance imaging (MRI), are prospectively and independently associated with intraparenchymal hemorrhage (IPH) incidence in a pooled population-based study.

METHODS

Among 4,872 participants initially free of clinical stroke in the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study, we assessed white matter grade (range, 0-9), reflecting increasing leukoaraiosis, and brain infarcts using MRI. Over a median of 13 years of follow-up, 71 incident, spontaneous IPH events occurred.

RESULTS

After adjustment for other IPH risk factors, the hazard ratios (95% confidence intervals) across white matter grades 0 to 1, 2, 3, and 4 to 9 were 1.00, 1.68 (0.86-3.30), 3.52 (1.80-6.89), and 3.96 (1.90-8.27), respectively (p for trend <0.0001). These hazard ratios were weakened only modestly (p for trend = 0.0003) with adjustment for MRI-defined brain infarcts. The IPH hazard ratios for 0, 1, 2, or ≥3 MRI-defined brain infarcts were 1.00, 1.97 (1.10-3.54), 2.00 (0.83-4.78), and 3.12 (1.31-7.43) (p for trend = 0.002), but these were substantially attenuated when adjusted for white matter grade (p for trend = 0.049).

INTERPRETATION

Greater MRI-defined burden of leukoaraiosis is a risk factor for spontaneous IPH. Spontaneous IPH should be added to the growing list of potential poor outcomes in people with leukoaraiosis.

Abstract 155: Risk of Seizures after Malignant MCA Stroke and Decompressive Hemicraniectomy

Background Post-stroke seizures (PSS) have a devastating effect on morale and may further impair an already compromised quality of life. The reported incidence of PSS is 5-12%, but may be higher in patients with malignant MCA stroke requiring decompressive hemicraniectomy. Seizure prophylaxis for stroke survivors is not recommended, and little guidance exists about the use of prophylactic antiepileptic drugs (AEDs) after neurosurgical procedures. We aimed to determine the incidence of seizures after hemicraniectomy in stroke survivors and to identify risk factors for development of seizures after stroke. Via telephone interview, we explored patients own experience after their stroke.

Methods We reviewed charts of patients aged 18-99 with malignant MCA infarction who underwent decompressive hemicraniectomy from Jan 1, 2002 to Dec 31, 2008. We looked for seizures that occurred after their stroke and for clinical and imaging factors related to those. All patients who consented to a telephone interview were contacted to inquire about seizure history. Seizure-free survival analysis was used, with log rank testing for associations.

Results We identified 38 patients, mean follow-up time was 504 days (IQR 140-857). Nearly half of patients suffered a seizure (18/38) and the seizures were difficult to control in 9/18. Four patients suffered their first seizure during initial hospitalization. For 14/18, the first seizure occurred after or around cranioplasty and mostly at home. Perioperative seizure prophylaxis was variable and did not influence seizure occurrence. Older age showed a trend towards increased seizure risk (log rank p=.09). Neither gender, race, severity, location or hemorrhagic transformation were associated with development of post-stroke seizures. Modified Rankin Scale score (mRS) at discharge was 4 or above in all patients. By last follow-up, 17/38 patients had a mRS of 3 or better. Patients who suffered a seizure did not feel well prepared for the possibility of PSS, and for some the seizures were considered a major setback. Among those who responded to the questionnaire (n=14, 12 had seizures), all would have wanted to know whether or not they were at high risk for developing PSS, and would have opted to take anti-epileptic medications for seizure prophylaxis.

Conclusions The frequency of seizures after malignant MCA stroke requiring decompressive hemicraniectomy is higher than expected, and the seizures often difficult to control.

Abstract 2695: A Clinical Prediction Rule for Pneumonia after Acute Stroke

INTRODUCTION: Dysphagia screens aim to reduce aspiration and pneumonia (PNA) after stroke. The frequency of PNA after stroke is low, especially in those with mild stroke who have not been intubated. We sought to identify a subset of patients with acute stroke who are at such low risk of PNA that bypassing a dysphagia screen would be justified.

METHODS: Harborview Medical Center, a tertiary care academic and primary stroke center, maintains a database of all patients admitted with stroke. From this, we identified 1,641 adults admitted to the Neurology service between 2007 and 2010 for acute ischemic or hemorrhagic stroke (HS). We excluded those with subarachnoid hemorrhage, those who had been intubated, except if only for a procedure, and those who lacked admission NIHSS. With PNA as outcome of interest, we sought associations with potential predictors using multiple logistic regression. We then created a score to predict PNA with each item’s weight based upon its magnitude of association with PNA in the multivariable model.

RESULTS: For the resulting 1,008 subjects, average age was 64.0 (+/- 18.2), 57.8% were male, 64.2% had ischemic stroke, and average NIHSS was 7.7 (+/- 8.5). PNA was diagnosed in 67 (6.6%) during the hospitalization. Age, stroke type, NIHSS, atrial fibrillation (AF), heart failure (HF), and chronic obstructive pulmonary disease (COPD) had significant univariate association with development of PNA. In multivariable models, all but AF retained significance. Adjusted odds ratios and 95% confidence intervals were: age (per year: 1.02, 1.00 - 1.04), NIHSS (per point: 1.04, 1.02 - 1.06), HS (1.67, 1.00 - 2.80), HF (2.62, 1.37 - 5.04), COPD (2.39, 1.23 - 4.64). The PNA score ranged from 0-10 with points assigned as follows: age ≥ 75 (2 pts), NIHSS 5-11 (1pts), NIHSS ≥ 12 (3 pts), HS (1 pt), HF (2 pts), COPD (2 pts). Only 8 cases of PNA were diagnosed in the 452 patients with a score of ≤1 (frequency 1.8%). The remaining 59 cases occurred in those 556 patients with a score of >1 (frequency 10.6%). This predictive model yielded a receiver operator curve with area under the curve of 0.76.

DISCUSSION: We developed a clinical prediction rule to estimate risk of PNA after acute stroke based upon age, stroke type and severity, and presence of HF and COPD. Presence of dysphagia was not one of the factors we examined because we were interested in seeing if we could identify a subgroup of patients with such low risk of PNA that bypassing a swallowing screen would be justified. Validation of the rule in an independent sample is needed before it could be used to influence clinical decisions. Limits of our study are the reliance on an existing database, which lacked potentially important predictors such as stroke location. Also, we do not know whether PNA was due to aspiration and stroke nor whether HF and COPD played a causal role or merely increased likelihood of PNA detection.

Birth order and narcolepsy risk among genetically susceptible individuals: a population-based case-control study

BACKGROUND

Birth order may play a role in autoimmune diseases and early childhood infections, both factors implicated in the etiology of narcolepsy. We investigated the association between birth order and narcolepsy risk in a population-based case-control study in which all study subjects were HLA-DQB1*0602 positive.

METHODS

Subjects were 18-50 years old, residents of King County, Washington, and positive for HLA-DQB1*0602. Birth order was obtained from administered interviews. We used logistic regression to generate odds ratios adjusted for income and African American race.

RESULTS

Analyses included 67 cases (mean age 34.3 [SD=9.1], 70.2% female) and 95 controls (mean age 35.1 [SD=8.8], 58.1% female). Associations for birth order were as follows: first born (cases 38.8% vs. controls 50.2%, OR=1.0; reference), second born (cases 29.9% vs. controls 32.9%, OR=1.6; 95% CI 0.7, 3.7), and third born or higher (cases 31.3% vs. controls 16.8%, OR=2.5; 95% CI 1.0, 6.0). A linear trend was significant (p<0.05). Sibling number, sibling gender, having children, and number of children did not differ significantly between narcolepsy cases and controls.

CONCLUSIONS

Narcolepsy risk was significantly associated with higher birth order in this population-based study of genetically susceptible individuals. This finding supports an environmental influence on narcolepsy risk through an autoimmune mechanism, early childhood infections, or both.

Swallowing screens after acute stroke: a systematic review

BACKGROUND AND PURPOSE

Swallowing screens after acute stroke identify those patients who do not need a formal swallowing evaluation and who can safely take food and medications by mouth. We conducted a systematic review to identify swallowing screening protocols that met basic requirements for reliability, validity, and feasibility.

METHODS

We searched MEDLINE and supplemented results with references identified through other databases, journal tables of contents, and bibliographies. All relevant references were reviewed and evaluated with specific criteria.

RESULTS

Of 35 protocols identified, 4 met basic quality criteria. These 4 had high sensitivities of ≥87% and high negative predictive values of ≥91% when a formal swallowing evaluation was used as the gold standard. Two protocols had greater sample sizes and more extensive reliability testing than the others.

CONCLUSIONS

We identified only 4 swallowing screening protocols for patients with acute stroke that met basic criteria. Cost-effectiveness of screening, including costs associated with false-positive results and impact of screening on morbidity, mortality, and length of hospital stay, requires elucidation.

Environmental tobacco smoke and Parkinson's disease

BACKGROUND

Parkinson's disease is inversely associated with cigarette smoking, but its relation with passive smoking or environmental tobacco smoke exposure is rarely examined.

METHODS

Within a case-control study, we assessed the association between Parkinson's disease and living or working with active smokers. Cases were newly diagnosed with idiopathic Parkinson's disease (n = 154) from western Washington State in 2002-2008. Age- and sex-matched controls (n = 173) were neurologically normal and unrelated to cases.

RESULTS

Compared with never active or passive tobacco smokers, we observed reduced Parkinson's disease risks for ever passive only smokers (OR, 0.34; 95% CI, 0.16-0.73), similar to those for ever active smokers (OR, 0.35; 95% CI, 0.17-0.73). Among persons whose only tobacco smoke exposure was passive smoking at home, risk was inversely associated with years exposed.

CONCLUSIONS

These observations parallel those well established for active smoking. However, it remains unresolved whether a true protective effect of tobacco smoke, generally detrimental to health, underlies these associations.

Abstract P265: Percutaneous Endoscopic Gastrostomy in Patients Discharged After Stroke in Washington State

OBJECTIVE: Explore the use of percutaneous endoscopic gastrostomy (PEG) in patients discharged after hospitalization for stroke in Washington State (WA).

METHODS: Patients were identified from administrative data for WA hospitals and included those discharged between 1995 and 2008 with stroke ICD-9 codes. PEG was defined by the presence of ICD-9 procedure codes. Using multivariate logistic regression, we sought independent associations with PEG for age, gender, stroke type, intubation, discharge year, co-morbid conditions, urban vs. rural home, and hospital type (stroke center or not).

RESULTS: A total of 118,785 stroke patients were discharged alive, 88% ischemic, 8% intracerebral hemorrhage (ICH), and 4% subarachnoid hemorrhage (SAH). Mean age was 73 years (SD 14), 54% were women, 44% were admitted to a stroke center, and 4.1% had PEG. Other complications of stroke included hemiplegia (28%), pneumonia (8%), and intubation (2%). Patient residence was urban for 83% and rural for 17%. Significant (p < 0.0001) independent associations with PEG included older age (OR ranging from 1.1, 95% CI .96-1.2, to 1.4, 95% CI 1.3-1.6, depending on age group), intubation (2.6, 2.3-2.9), hemiplegia (2.3, 2.1-2.4), stroke type (vs. ischemic stroke: ICH 2.0, 1.8-2.2; SAH 1.6, 1.3-1.8), atrial fibrillation (1.4, 1.3-1.5), congestive heart failure (1.2, 1.1-1.3), acute myocardial infarction (1.2, 1.0-1.4), pneumonia (6.0, 5.6-6.4), stroke center (1.1, 1.1-1.2), and rural home address (.76, .70-.83). PEG was not associated with discharge time period, but this effect was modified by eventual stroke center status (p < 0.0001).

CONCLUSIONS: In this large population-based study, we found a lower frequency of PEG in stroke survivors than previously reported, possibly reflecting misclassification in our study, selection bias in prior studies, or both. PEG was significantly associated with stroke type and medical complications, particularly pneumonia and endotracheal intubation, likely reflecting stroke severity. The rising probability of PEG at stroke centers may suggest that severely affected patients are increasingly being transferred to stroke centers. Additional studies are need to understand better the criteria for and the utility of PEG in stroke survivors.

Fasting and post-glucose load measures of insulin resistance and risk of ischemic stroke in older adults

BACKGROUND AND PURPOSE

Few studies have assessed post-glucose load measures of insulin resistance and ischemic stroke risk, and data are sparse for older adults. We investigated whether fasting and post-glucose load measures of insulin resistance were related to incident ischemic stroke in nondiabetic, older adults.

METHODS

Participants were men and women in the Cardiovascular Health Study, age 65+ years and without prevalent diabetes or stroke at baseline, followed for 17 years for incident ischemic stroke. The Gutt insulin sensitivity index was calculated from baseline body weight and from fasting and 2-hour postload insulin and glucose; a lower Gutt index indicates higher insulin resistance.

RESULTS

Analyses included 3442 participants (42% men) with a mean age of 73 years. Incidence of ischemic stroke was 9.8 strokes per 1000 person-years. The relative risk (RR) for lowest quartile versus highest quartile of Gutt index was 1.64 (95% CI, 1.24-2.16), adjusted for demographics and prevalent cardiovascular and kidney disease. Similarly, the adjusted RR for highest quartile versus lowest quartile of 2-hour glucose was 1.84 (95% CI, 1.39-2.42). In contrast, the adjusted RR for highest quartile versus lowest quartile of fasting insulin was 1.10 (95% CI, 0.84-1.46).

CONCLUSIONS

In nondiabetic, older adults, insulin resistance measured by Gutt index or 2-hour glucose, but not by fasting insulin, was associated with risk of incident ischemic stroke.

Carotid intima-media thickness, electrocardiographic left ventricular hypertrophy, and incidence of intracerebral hemorrhage

BACKGROUND AND PURPOSE

Carotid intima-media thickness and electrocardiographic left ventricular hypertrophy are 2 subclinical cardiovascular disease measures associated with increased risk of total and ischemic strokes. Increased intima-media thickness and electrocardiographic left ventricular hypertrophy also may reflect end-organ hypertensive effects. Information is scant on the associations of these subclinical measures with intracerebral hemorrhage (ICH). We hypothesized that greater carotid intima-media thickness and the presence of electrocardiographic left ventricular hypertrophy would be independently associated with increased ICH incidence.

METHODS

Among 18,155 participants initially free of stroke in the Atherosclerosis Risk in Communities Study (ARIC) and the Cardiovascular Health Study (CHS), we assessed carotid intima-media thickness, carotid plaque, and electrocardiographic left ventricular hypertrophy. Over a median of 18 years of follow-up, 162 incident ICH events occurred.

RESULTS

After adjustment for other ICH risk factors, carotid intima-media thickness was associated positively with incidence of ICH in both ARIC and CHS. The risk was lowest in study-specific Quartile 1, elevated 1.6- to 2.6-fold in Quartiles 2 to 3, and elevated 2.5 to 3.7-fold in Quartile 4 (P<0.05 for both studies). In CHS, having a carotid plaque was associated with a 2-fold (95% CI, 1.1-3.4) greater ICH risk than having no plaque, but only 1.2-fold (95% CI, 0.76-2.0) greater ICH risk in ARIC. Electrocardiographic left ventricular hypertrophy carried a hazard ratio of ICH of 1.7 (95% CI, 0.77-3.7) in CHS and 2.8 (95% CI, 1.2-6.4) in ARIC.

CONCLUSIONS

Our data suggest that people with carotid atherosclerosis and possibly left ventricular hypertrophy are at increased risk not only of ischemic stroke, but also of ICH.

Neighborhood disadvantage and ischemic stroke: the Cardiovascular Health Study (CHS)

BACKGROUND AND PURPOSE

Neighborhood characteristics may influence the risk of stroke and contribute to socioeconomic disparities in stroke incidence. The objectives of this study were to examine the relationship between neighborhood socioeconomic status and incident ischemic stroke and examine potential mediators of these associations.

METHODS

We analyzed data from 3834 whites and 785 blacks enrolled in the Cardiovascular Health Study, a multicenter, population-based, longitudinal study of adults ages≥65 years from 4 US counties. The primary outcome was adjudicated incident ischemic stroke. Neighborhood socioeconomic status was measured using a composite of 6 census tract variables. Race-stratified multilevel Cox proportional hazard models were constructed adjusted for sociodemographic, behavioral, and biological risk factors.

RESULTS

Among whites, in models adjusted for sociodemographic characteristics, stroke hazard was significantly higher among residents of neighborhoods in the lowest compared with the highest neighborhood socioeconomic status quartile (hazard ratio, 1.32; 95% CI, 1.01-1.72) with greater attenuation of the hazard ratio after adjustment for biological risk factors (hazard ratio, 1.16; 0.88-1.52) than for behavioral risk factors (hazard ratio, 1.30; 0.99-1.70). Among blacks, we found no significant associations between neighborhood socioeconomic status and ischemic stroke.

CONCLUSIONS

Higher risk of incident ischemic stroke was observed in the most disadvantaged neighborhoods among whites, but not among blacks. The relationship between neighborhood socioeconomic status and stroke among whites appears to be mediated more strongly by biological than behavioral risk factors.

Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk

Blood pressure (BP) is a heritable trait¹ influenced by multiple biological pathways and is responsive to environmental stimuli. Over one billion people worldwide have hypertension (BP ≥140 mm Hg systolic [SBP] or ≥90 mm Hg diastolic [DBP])². Even small increments in BP are associated with increased risk of cardiovascular events³. This genome-wide association study of SBP and DBP, which used a multi-stage design in 200,000 individuals of European descent, identified 16 novel loci: six of these loci contain genes previously known or suspected to regulate BP (GUCY1A3-GUCY1B3; NPR3-C5orf23; ADM; FURIN-FES; GOSR2; GNAS-EDN3); the other 10 provide new clues to BP physiology. A genetic risk score based on 29 genome-wide significant variants was associated with hypertension, left ventricular wall thickness, stroke, and coronary artery disease, but not kidney disease or kidney function. We also observed associations with BP in East Asian, South Asian, and African ancestry individuals. Our findings provide new insights into the genetics and biology of BP, and suggest novel potential therapeutic pathways for cardiovascular disease prevention.

Genome-wide association studies of cerebral white matter lesion burden: the CHARGE consortium

OBJECTIVE

White matter hyperintensities (WMHs) detectable by magnetic resonance imaging are part of the spectrum of vascular injury associated with aging of the brain and are thought to reflect ischemic damage to the small deep cerebral vessels. WMHs are associated with an increased risk of cognitive and motor dysfunction, dementia, depression, and stroke. Despite a significant heritability, few genetic loci influencing WMH burden have been identified.

METHODS

We performed a meta-analysis of genome-wide association studies (GWASs) for WMH burden in 9,361 stroke-free individuals of European descent from 7 community-based cohorts. Significant findings were tested for replication in 3,024 individuals from 2 additional cohorts.

RESULTS

We identified 6 novel risk-associated single nucleotide polymorphisms (SNPs) in 1 locus on chromosome 17q25 encompassing 6 known genes including WBP2, TRIM65, TRIM47, MRPL38, FBF1, and ACOX1. The most significant association was for rs3744028 (p(discovery) = 4.0 × 10(-9) ; p(replication) = 1.3 × 10(-7) ; p(combined) = 4.0 × 10(-15) ). Other SNPs in this region also reaching genome-wide significance were rs9894383 (p = 5.3 × 10(-9) ), rs11869977 (p = 5.7 × 10(-9) ), rs936393 (p = 6.8 × 10(-9) ), rs3744017 (p = 7.3 × 10(-9) ), and rs1055129 (p = 4.1 × 10(-8) ). Variant alleles at these loci conferred a small increase in WMH burden (4-8% of the overall mean WMH burden in the sample).

INTERPRETATION

This large GWAS of WMH burden in community-based cohorts of individuals of European descent identifies a novel locus on chromosome 17. Further characterization of this locus may provide novel insights into the pathogenesis of cerebral WMH.

Association of annular calcification and aortic valve sclerosis with brain findings on magnetic resonance imaging in community dwelling older adults: the cardiovascular health study

OBJECTIVES

The objective of this study was to investigate the associations of mitral annular calcification, aortic annular calcification, and aortic valve sclerosis with covert magnetic resonance imaging (MRI)-defined brain infarcts.

BACKGROUND

Clinically silent brain infarcts defined by MRI are associated with increased risk for cognitive decline, dementia, and future overt stroke. Left-sided cardiac valvular and annular calcifications are suspected as risk factors for clinical ischemic stroke.

METHODS

A total of 2,680 CHS (Cardiovascular Health Study) participants without clinical histories of stroke or transient ischemic attack underwent brain MRI in 1992 and 1993, 1 to 2 years before echocardiographic exams (1994 to 1995).

RESULTS

The mean age of the participants was 74.5 ± 4.8 years, and 39.3% were men. The presence of any annular or valvular calcification (mitral annular calcification, aortic annular calcification, or aortic valve sclerosis), mitral annular calcification alone, or aortic annular calcification alone was significantly associated with a higher prevalence of covert brain infarcts in unadjusted analyses (p < 0.01 for all). In models adjusted for age, sex, race, body mass index, physical activity, creatinine, systolic blood pressure, total cholesterol, high-density lipoprotein cholesterol, smoking, diabetes, coronary heart disease, and congestive heart failure, the presence of any annular or valve calcification remained associated with covert brain infarcts (risk ratio: 1.24; 95% confidence interval: 1.05 to 1.47). The degree of annular or valvular calcification severity showed a direct relation with the presence of covert MRI findings.

CONCLUSIONS

Left-sided cardiac annular and valvular calcifications are associated with covert MRI-defined brain infarcts. Further study is warranted to identify mechanisms and determine whether intervening in the progression of annular and valvular calcification could reduce the incidence of covert brain infarcts as well as the associated risk for cognitive impairment and future stroke.

Progression of magnetic resonance imaging-defined brain vascular disease predicts vascular events in elderly: the Cardiovascular Health Study

BACKGROUND AND PURPOSE

To determine whether progression of MRI-defined vascular disease predicts subsequent vascular events in the elderly.

METHODS

The Cardiovascular Health Study, a longitudinal cohort study of vascular disease in the elderly, allows us to address this question because its participants had 2 MRI scans≈5 years apart and have been followed for ≈9 years since the follow-up scan for incident vascular events.

RESULTS

Both MRI-defined incident infarcts and worsened white matter grade were significantly associated with heart failure, stroke, and death, but not transient ischemic attacks, angina, or myocardial infarction. Strongest associations occurred when both incident infarcts and worsened white matter grade were present for heart failure (hazard ratio, 1.79; 95% confidence interval, 1.18-2.73), stroke (hazard ratio, 2.58; 95% confidence interval, 1.53-4.36), death (hazard ratio, 1.69; 95% confidence interval, 1.28-2.24), and cardiovascular death (hazard ratio, 1.97; 95% confidence interval, 1.24-3.14).

CONCLUSIONS

Progression of MRI-defined vascular disease identifies elderly people at increased risk for subsequent heart failure, stroke, and death. Whether aggressive risk factor management would reduce risk is unknown.

The risk of Parkinson disease associated with urate in a community-based cohort of older adults

BACKGROUND/AIMS

Studies suggest an inverse association between urate concentration and the risk of Parkinson disease (PD). We investigated this in the Cardiovascular Health Study in an elderly community-based cohort of adults.

METHODS

The association of baseline urate (µmol/l) and incident PD over 14 years was assessed with locally weighted scatterplot smoothing (LOESS) regression from which categories of low (<300 µmol/l), middle (300-500 µmol/l), and high (>500 µmol/l) urate ranges were derived. Multivariate logistic regression models assessed the risk of PD for each urate range. Linear and quadratic terms were tested when modeling the association between urate and the risk of PD.

RESULTS

Women had significantly lower urate concentrations than did men [316.8 µmol/l (SD 88.0) vs. 367.4 µmol/l (SD 87.7), p < 0.0001] and in women no associations between urate and PD risk were observed. In men, LOESS curves suggested a U-shaped or threshold effect between urate and PD risk. With the middle range as reference, the risk of developing PD was significantly increased for urate <300 µmol/l (OR 1.69, 95% CI 1.03-2.78) but not for urate >500 µmol/l (OR 1.55, 95% CI 0.72-3.32) in men. A negative linear term was significant for urate <500 µmol/l, and across the entire range a convex quadratic term was significant.

CONCLUSIONS

Results suggest a more complex relationship than previously reported between urate levels and the risk of PD in men. Low urate concentrations were associated with a higher PD risk and high urate concentrations were not associated with a further decrease in PD risk.

Hospitalization for infection and risk of acute ischemic stroke: the Cardiovascular Health Study

BACKGROUND AND PURPOSE

Little is known about the acute precipitants of ischemic stroke, although evidence suggests infections contribute to risk. We hypothesized that acute hospitalization for infection is associated with the short-term risk of stroke.

METHODS

The case-crossover design was used to compare hospitalization for infection during case periods (90, 30, or 14 days before an incident ischemic stroke) and control periods (equivalent time periods exactly 1 or 2 years before stroke) in the Cardiovascular Health Study, a population-based cohort of 5888 elderly participants from 4 US sites. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated by conditional logistic regression. Confirmatory analyses assessed hazard ratios of stroke from Cox regression models, with hospitalization for infection as a time-varying exposure.

RESULTS

During a median follow-up of 12.2 years, 669 incident ischemic strokes were observed in participants without a baseline history of stroke. Hospitalization for infection was more likely during case than control time periods; for 90 days before stroke, OR=3.4 (95% CI, 1.8 to 6.5). The point estimates of risks were higher when we examined shorter intervals: for 30 days, OR=7.3 (95% CI, 1.9 to 40.9), and for 14 days, OR=8.0 (95% CI, 1.7 to 77.3). In survival analyses, risk of stroke was associated with hospitalization for infection in the preceding 90 days, adjusted hazard ratio=2.4 (95% CI, 1.6 to 3.4).

CONCLUSIONS

Hospitalization for infection is associated with a short-term increased risk of stroke, with higher risks observed for shorter intervals preceding stroke.

The Vietnam War and medical research: untold legacy of the U.S. Doctor Draft and the NIH "Yellow Berets"

PURPOSE

From the outbreak of the Korean War in 1950 through the end of the Vietnam War in 1973, many American physicians were inducted into military service through the Doctor Draft. Some fulfilled their obligations by conducting clinical research in the National Institutes of Health (NIH) Associate Training Program (ATP) and later labeled themselves "Yellow Berets." The authors examined the history of the ATP and its influence on NIH associates' future careers.

METHOD

Via interviews with former associates and archival research, the authors explored the training and collaboration in the ATP during 1953-1973. Using databases, they compared later academic positions of associates with those of nonassociate peers who also entered academia and identified associates with prestigious awards or honorary society memberships.

RESULTS

The physician-scientists trained in the selective ATP were highly qualified individuals who received training and networking opportunities not available to others. They were approximately 1.5 times as likely as nonassociates to become a full professor, twice as likely to become chair of a department, and three times as likely to become a dean. Associates were also more likely to hold positions at top-ranked medical schools, to fill leadership roles in the NIH, and to win prestigious awards and honorary society memberships.

CONCLUSIONS

The cadre of physician-scientists trained in the ATP during the Doctor Draft rose through the academic ranks to leadership roles and continued their productive scientific collaborations. Their legacy continues to have implications for medical research today, particularly for training programs in clinical research.

Association of coagulation-related and inflammation-related genes and factor VIIc levels with stroke: the Cardiovascular Health Study

BACKGROUND

Thrombosis and inflammation are critical in stroke etiology, but associations of coagulation and inflammation gene variants with stroke, and particularly factor VII levels, are inconclusive.

OBJECTIVES

To test the associations between 736 single-nucleotide polymorphisms (SNPs) between tagging haplotype patterns of 130 coagulation and inflammation genes, and stroke events, in the 5888 participants aged ≥ 65 years of the observational Cardiovascular Health Study cohort.

PATIENTS/METHODS

With 16 years of follow-up, age-adjusted and sex-adjusted Cox models were used to estimate associations of SNPs and FVIIc levels with future stroke.

RESULTS

Eight hundred and fifteen strokes occurred in 5255 genotyped participants without baseline stroke (748 ischemic strokes; 586 among whites). Among whites, six SNPs were associated with stroke, with a nominal P-value of < 0.01: rs6046 and rs3093261 (F7); rs4918851 and rs3781387 (HABP2); and rs3138055 (NFKB1A) and rs4648004 (NFKB1). Two of these SNPs were associated with FVIIc levels (units of percentage activity): rs6046 (β = -18.5, P = 2.38 × 10(-83)) and rs3093261 (β = 2.99, P = 3.93 × 10(-6)). After adjustment for age, sex, race, and cardiovascular risk factors, the association of FVIIc quintiles (Q) with stroke were as follows (hazard ratio; 95% confidence interval): Q1, reference; Q2, 1.4, 1.1-1.9); Q3, 1.1, 0.8-1.5); Q4, 1.5, 1.1-2.0); and Q5, 1.6, 1.2-2.2). Associations between SNPs and stroke were independent of FVIIc levels.

CONCLUSIONS

Variations in FVII-related genes and FVIIc levels were associated with risk of incident ischemic stroke in this elderly cohort, suggesting a potential causal role for FVII in stroke etiology.

Measures of adiposity and future risk of ischemic stroke and coronary heart disease in older men and women

The relation between measures of general and central adiposity and individual cardiovascular endpoints remains understudied in older adults. This study investigated the association of measures of body size and composition with incident ischemic stroke or coronary heart disease (1989-2007) in 3,754 community-dwelling US adults aged 65-100 years. Standardized anthropometry and bioelectric impedance measurements were obtained at baseline. Body mass index at age 50 years (BMI50) was calculated on the basis of recalled weight. Although only waist/hip ratio was significantly associated with ischemic stroke in quintile analysis in women, dichotomized body mass index (BMI) (≥ 30 kg/m²) was the only significant predictor in men. For coronary heart disease, there were significant positive adjusted associations for all adiposity measures, without interaction by sex. This was true for both quintiles and conventional cutpoints for obesity, although BMI-defined overweight (25-29.9 kg/m² was significant at midlife but not at baseline. Strengths of association for extreme quintiles (quintile 5 vs. quintile 1) were broadly comparable, but the highest effect estimates were for waist/hip ratio (hazard ratio = 1.56, 95% confidence interval: 1.25, 1.94) and BMI50 (hazard ratio = 1.71, 95% confidence interval: 1.37, 2.14), both of which remained significant after adjustment for mediators, BMI, or each other. Whether these differences translate to better risk prediction will require meta-analytical approaches, as will determination of prognostic cutpoints.

Post hoc Parkinson's disease: identifying an uncommon disease in the Cardiovascular Health Study

BACKGROUND

Although ongoing cohort studies offer a unique opportunity to apply existing information collected prospectively to further the scientific understanding of Parkinson's disease (PD), they typically have limited information for clinical diagnosis.

METHODS

We used combinations of self-report, International Classification of Diseases - 9th edition codes and antiparkinsonian medications to identify PD in the Cardiovascular Health Study. To determine whether the expected inverse association between smoking and PD is evident using our outcome definitions, we assessed baseline smoking characteristics for various definitions of PD.

RESULTS

We identified 60 cases with prevalent PD (1.0%; 95% confidence interval, CI = 0.8-1.3%) and 154 with incident PD by year 14. Clear associations were observed for current smokers (odds ratio, OR = 0.50; 95% CI = 0.26-0.95) and for those who smoked ≥50 pack-years (OR = 0.53; 95% CI = 0.29-0.96). Estimates for smoking were similar when ≥2 data sources were required. Estimates for self-report alone were attenuated towards null.

CONCLUSIONS

Using multiple data sources to identify PD represents an alternative method of outcome identification in a cohort that would otherwise not be possible for PD research. Ongoing cohort studies can provide settings in which rapid replication and explorations of new hypotheses for PD are possible.

Albuminuria and the risk of incident stroke and stroke types in older adults

BACKGROUND

The kidney biomarker that best reflects risk of stroke is unknown. We sought to evaluate the association of stroke with 3 kidney biomarkers: albuminuria, cystatin C, and glomerular filtration rate.

METHODS

These 3 biomarkers were determined in 3,287 participants without history of stroke from the Cardiovascular Health Study, a longitudinal cohort study of men and women age 65 years and older from 4 US communities. The biomarkers were albuminuria ascertained using urinary albumin-to-creatinine ratio (UACR) from morning spot urine, creatinine-based estimated glomerular filtration rate (eGFR), and cystatin C. Outcomes were incident stroke (any, ischemic, or hemorrhagic) during follow-up between 1996 and 2006.

RESULTS

A total of 390 participants had an incident stroke: 81% ischemic, 12% hemorrhagic, and 7% unclassified. In adjusted Cox regression models, UACR was more strongly related to any stroke, ischemic stroke, and hemorrhagic stroke than eGFR and cystatin C. The hazard ratio (HR) of any stroke comparing the top to bottom quintile of UACR was 2.10 (95% confidence interval [CI] 1.47-3.00), while HR for eGFR was 1.29 (95% CI 0.91-1.84) and for cystatin C was 1.22 (95% CI 0.85-1.74). When considering clinically relevant categories, elevated UACR was associated with increased hazard of any stroke and ischemic stroke regardless of eGFR or cystatin C categories.

CONCLUSIONS

UACR was the kidney biomarker most strongly associated with risk of incident stroke. Results in this elderly cohort may not be applicable to younger populations. These findings suggest that measures of glomerular filtration and permeability have differential effects on stroke risk.

Environmental toxins and risk of narcolepsy among people with HLA DQB1*0602

One etiologic model for narcolepsy suggests that some environmental toxin selectively and irreversibly destroys hypocretin-producing cells in individuals with human leukocyte antigen (HLA) DQB1(*)0602. Between 2001 and 2005, the authors conducted a population-based case-control study in King County, Washington to examine narcolepsy risk in relation to toxins found in jobs, hobbies, and other non-vocational activities. Sixty-seven cases and 95 controls were enrolled; all were between ages 18 and 50 and positive for HLA DQB1(*)0602. All were administered in-person interviews about jobs, hobbies or other non-vocational activities before age 21. All analyses were adjusted for African-American race and income. Risk increased significantly for jobs involving heavy metals (odds ratio [OR]=4.7; 95% confidence interval [CI]: 1.5, 14.5) and for highest levels of exposure to woodwork (OR: 3.0; 95% CI: 1.0, 8.9), fertilizer (OR=3.1; 95% CI: 1.1, 9.1), and bug or weed killer (OR=4.5; 95% CI: 1.5, 13.4). Associations were of borderline significance for activities involving ceramics, pesticides, and painting projects. Significant dose-response relationships were evident for jobs involving metals (p<0.03), paints (p<0.03), and bug or weed killer (p<0.02). Additional studies are needed to replicate these findings and continue the search for specific toxins that could damage hypocretin neurons in genetically susceptible people.

Cognition and the risk of hospitalization for serious falls in the elderly: results from the Cardiovascular Health Study

BACKGROUND

Many elderly adults fall every year, sometimes resulting in serious injury and hospitalization. Although impaired cognition is a risk factor for injurious falls, little is known about cognitive decline above the threshold of impairment and risk of serious falls in community-dwelling seniors.

METHODS

In total, 702 of 5,356 older adults participating in the Cardiovascular Health Study experienced an injurious fall between 1990 and 2005, as indicated by hospitalization records. General cognition was measured annually with the Modified Mini-Mental State Examination and processing speed with the Digit Symbol Substitution Test. The Cox regression model was used to calculate hazard ratio and 95% confidence interval with and without time-dependent covariates and adjusted for known risk factors.

RESULTS

Participants with slightly decreased Digit Symbol Substitution Test scores were at increased risk for a serious fall (hazard ratio = 1.58, 95% confidence interval = 1.15-2.17). The risk continued to increase with each quartile decrease in Digit Symbol Substitution Test score. Participants without prevalent cardiovascular disease at baseline and decreased Modified Mini-Mental State Examination scores (80-89) had a 45% increased risk for a serious fall and those at high risk for dementia (<80) were at twice the risk as participants scoring above 90 (hazard ratio = 2.16, 95% confidence interval = 1.60-2.91).

CONCLUSIONS

Both decreased general cognition and decreased processing speed appear to be potential risk factors for serious falls in the elderly. When assessing the risk of serious falls in elderly patients, clinicians should consider usual factors like gait instability and sensory impairment as well as less obvious ones such as cardiovascular disease and cognitive function in nondemented adults.

Lethal giant cell arteritis with multiple ischemic strokes despite aggressive immunosuppressive therapy

Two patients with giant cell arteritis (GCA) had a malignant course despite aggressive immunosuppressive therapy. A 63-year-old woman presented with symptoms of headache, jaw claudication, scalp paresthesia, and visual disturbances. A temporal artery biopsy showed GCA. While on prednisone, she suffered ischemic strokes, and serial cerebral angiograms demonstrated bilateral, severe and progressive narrowing of distal vertebral and internal carotid arteries. Despite escalating immunosuppressive therapies, she suffered more infarcts and eventually died. Postmortem examination of arteries showed no active inflammation. A 65-year-old man presented with extrapyramidal symptoms though no symptoms typical of GCA. Imaging showed multiple ischemic strokes. Because serial angiograms demonstrated findings similar to the first patient, he underwent temporal artery biopsy that showed GCA. He died 7 months after his presentation with complications of aggressive immunosuppressive therapy. These two patients confirm that GCA can follow a lethal course despite escalating immunosuppressive therapies. Our two patients were unique in that eventually both anterior and posterior circulations were involved bilaterally in a characteristic location where the arteries penetrate the dura. This pattern should always raise the possibility of GCA and, if confirmed, should prompt aggressive immunosuppressive therapy. The dismal outcomes despite this approach may suggest a non-inflammatory arteriopathy, as seen on necropsy in one of our patients. Such an arteriopathy may require novel therapies to be considered for this severe variant of GCA.

Genome-wide analysis of genetic loci associated with Alzheimer disease

CONTEXT

Genome-wide association studies (GWAS) have recently identified CLU, PICALM, and CR1 as novel genes for late-onset Alzheimer disease (AD).

OBJECTIVES

To identify and strengthen additional loci associated with AD and confirm these in an independent sample and to examine the contribution of recently identified genes to AD risk prediction in a 3-stage analysis of new and previously published GWAS on more than 35,000 persons (8371 AD cases).

DESIGN, SETTING, AND PARTICIPANTS

In stage 1, we identified strong genetic associations (P < 10(-3)) in a sample of 3006 AD cases and 14,642 controls by combining new data from the population-based Cohorts for Heart and Aging Research in Genomic Epidemiology consortium (1367 AD cases [973 incident]) with previously reported results from the Translational Genomics Research Institute and the Mayo AD GWAS. We identified 2708 single-nucleotide polymorphisms (SNPs) with P < 10(-3). In stage 2, we pooled results for these SNPs with the European AD Initiative (2032 cases and 5328 controls) to identify 38 SNPs (10 loci) with P < 10(-5). In stage 3, we combined data for these 10 loci with data from the Genetic and Environmental Risk in AD consortium (3333 cases and 6995 controls) to identify 4 SNPs with P < 1.7x10(-8). These 4 SNPs were replicated in an independent Spanish sample (1140 AD cases and 1209 controls). Genome-wide association analyses were completed in 2007-2008 and the meta-analyses and replication in 2009.

MAIN OUTCOME MEASURE

Presence of Alzheimer disease.

RESULTS

Two loci were identified to have genome-wide significance for the first time: rs744373 near BIN1 (odds ratio [OR],1.13; 95% confidence interval [CI],1.06-1.21 per copy of the minor allele; P = 1.59x10(-11)) and rs597668 near EXOC3L2/BLOC1S3/MARK4 (OR, 1.18; 95% CI, 1.07-1.29; P = 6.45x10(-9)). Associations of these 2 loci plus the previously identified loci CLU and PICALM with AD were confirmed in the Spanish sample (P < .05). However, although CLU and PICALM were confirmed to be associated with AD in this independent sample, they did not improve the ability of a model that included age, sex, and APOE to predict incident AD (improvement in area under the receiver operating characteristic curve from 0.847 to 0.849 in the Rotterdam Study and 0.702 to 0.705 in the Cardiovascular Health Study).

CONCLUSIONS

Two genetic loci for AD were found for the first time to reach genome-wide statistical significance. These findings were replicated in an independent population. Two recently reported associations were also confirmed. These loci did not improve AD risk prediction. While not clinically useful, they may implicate biological pathways useful for future research.