Procalcitonin and Midregional Proatrial Natriuretic Peptide as Markers of Ischemic Stroke: The Northern Manhattan Study

BACKGROUND AND PURPOSE

Chronic infections and neuroendocrine dysfunction may be risk factors for ischemic stroke (IS). We hypothesized that selected blood biomarkers of infection (procalcitonin [PCT]), hypothalamic-pituitary-axis function (copeptin), and hemodynamic dysfunction (midregional proatrial natriuretic peptide [MRproANP]) are associated with incident IS risk in the multiethnic, urban Northern Manhattan Study (NOMAS) cohort.

METHODS

A nested case-control study was performed among initially stroke-free participants. Cases were defined as first IS (n=172). We randomly selected controls among those who did not develop an event (n=344). We calculated Cox proportional hazards models with inverse probability weighting to estimate the association of blood biomarkers with risk of stroke after adjusting for demographic, behavioral, and medical risk factors.

RESULTS

Those with PCT and MRproANP, but not copeptin, in the top quartile, compared with the lowest quartile, were associated with IS (for PCT adjusted hazard ratio [HR], 1.9; 95% confidence interval [CI], 1.0-3.8 and for MRproANP adjusted HR, 3.5; 95% CI, 1.6-7.5). The associations of PCT and MRproANP differed by stroke etiology; PCT levels in the top quartile were particularly associated with small vessel stroke (adjusted HR, 5.1; 95% CI, 1.4-18.7) and MRproANP levels with cardioembolic stroke (adjusted HR, 16.3; 95% CI, 3.7-70.9).

CONCLUSIONS

Higher levels of PCT, a marker of infection, and MRproANP, a marker for hemodynamic stress, were independently associated with IS risk. PCT was specifically associated with small vessel and MRproANP with cardioembolic stroke risk. Further study is needed to validate these biomarkers and determine their significance in stroke risk prediction and prevention.

High-sensitivity C-reactive protein and interleukin-6-dominant inflammation and ischemic stroke risk: the northern Manhattan study

BACKGROUND AND PURPOSE

Interleukin-6 (IL-6) is a proinflammatory cytokine with known autoregulatory feedback mechanisms. We hypothesized that elevated high-sensitivity C-reactive protein (hsCRP) relative to IL-6 confers an increased risk of ischemic stroke (IS), and low hsCRP relative to IL-6 a decreased risk, for individuals in the prospective, multiethnic, population-based Northern Manhattan Study (NOMAS).

METHODS

Serum hsCRP and IL-6 were measured in NOMAS participants at baseline. We created a trichotomized predictor based on the dominant biomarker in terms of quartiles: hsCRP-dominant, IL-6-dominant, and codominant groups. Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals for the association between inflammatory biomarker group status and risk of incident IS.

RESULTS

Of 3298 participants, both hsCRP and IL-6 were available in 1656 participants (mean follow-up, 7.8 years; 113 incident IS). The hsCRP-dominant group had increased risk of IS (adjusted hazard ratio, 2.62; 95% confidence interval, 1.56-4.41) and the IL-6-dominant group had decreased risk (adjusted hazard ratio, 0.38; 95% confidence interval, 0.18-0.82) when compared with the referent group, after adjusting for potential confounders. Model fit was improved using the inflammation-dominant construct, over either biomarker alone.

CONCLUSIONS

In this multiethnic cohort, when hsCRP-quartile was higher than IL-6 quartile, IS risk was increased, and conversely when IL-6 quartiles were elevated relative to hsCRP, IS risk was decreased. Construct validity requires confirmation in other cohorts.

Lipoprotein-associated phospholipase A2 is associated with atherosclerotic stroke risk: the Northern Manhattan Study

Background

Lipoprotein-associated phospholipase A2 (LpPLA2) levels are associated with stroke, though whether this extends to all populations and stroke subtypes is unknown.

Methods

Serum samples from stroke-free community participants in the Northern Manhattan Study were assayed for LpPLA2 mass and activity. Participants were followed annually for stroke. Cox-proportional-hazard models were fitted to estimate hazard-ratios and 95% confidence intervals (HR, 95% CI) for the association of LpPLA2 levels with ischemic stroke (IS), after adjusting for demographic and medical risk factors.

Results

Serum samples were available in 1946 participants, of whom 151 (7.8%) experienced a first IS during median follow-up 11 years. Mean age was 69 (SD 10), 35.6% were men, 20% non-Hispanic Whites, 22% non-Hispanic Blacks, and 55% Hispanics. LpPLA2 mass and activity levels were not associated with overall IS risk.

LpPLA2 mass but not activity levels were associated with strokes due to large artery atherosclerosis (LAA; adjusted HR per SD 1.55, 95% CI 1.17–2.04). There was a dose-response relationship with LAA (compared to first quartile, 2nd quartile HR = 1.43, 95% CI 0.23–8.64; 3rd quartile HR = 4.47, 95% CI 0.93–21.54; 4th quartile HR = 5.07, 95% CI 1.07–24.06). The associations between LpPLA2-mass and LAA-stroke risk differed by race-ethnicity (p = 0.01); LpPLA2-mass was associated with increased risk of LAA among non-Hispanic Whites (adjusted HR per SD 1.44, 95% CI 0.98–2.11), but not other race-ethnic groups.

Conclusion

LpPLA2-mass levels were associated with risk of atherosclerotic stroke among non-Hispanic White participants, but not in other race-ethnic groups in the cohort. Further study is needed to confirm these race-ethnic differences and the reasons for them.

Diabetes predicts long-term disability in an elderly urban cohort: the Northern Manhattan Study

PURPOSE

There are limited data on vascular predictors of long-term disability in Hispanics. We hypothesized that (1) functional status declines over time and (2) vascular risk factors predict functional decline.

METHODS

The Northern Manhattan Study contains a population-based study of 3298 stroke-free individuals aged 40 years or older, followed for median 11 years. The Barthel Index (BI) was assessed annually. Generalized estimating equations and Cox models were adjusted for demographic, medical, and social risk factors. Stroke and myocardial infarction occurring during follow-up were censored in sensitivity analysis. Secondarily, motor and nonmotor domains of the BI were analyzed.

RESULTS

Mean age (standard deviation) of the cohort (n = 3298) was 69.2 (10) years, 37% were male, 52% Hispanic, 22% diabetic, and 74% hypertensive. There was a mean annual decline of 1.02 BI points (P < .0001). Predictors of decline in BI included age, female sex, diabetes, depression, and normocholesterolemia. Results did not change with censoring. We found similar predictors of BI for motor and nonmotor domains.

CONCLUSION

In this large, population-based, multiethnic study with long-term follow-up, we found a 1% mean decline in function per year that did not change when vascular events were censored. Diabetes predicted functional decline in the absence of clinical vascular events.

Interleukin 6 plasma concentration associates with cognitive decline: the northern Manhattan study

BACKGROUND

Interleukin 6 (IL-6) is an inflammatory cytokine that has been associated with vascular disease and cognitive impairment, but few studies have examined these relationships in population-based studies that include Hispanic and Black people who often have a greater prevalence of vascular risk factors and are at an elevated risk of dementia than Whites. We examined relative elevations of plasma IL-6 concentrations in relation to cognitive decline in a stroke-free racially/ethnically diverse community-based sample from Northern Manhattan.

METHODS

We used mixed effects models to measure the effect of IL-6 on change in performance on the modified Telephone Interview for Cognitive Status (TICS-m) measured annually in our cohort, adjusting for sociodemographic and vascular risk factors.

RESULTS

There were 1,224 participants with IL-6 levels (median 1.5 pg/ml, interquartile range 0.83-2.57 pg/ml) and TICS-m data available (mean = 31.6 points, SD 6.5). The mean age was 71 (SD 9.3; 64% women, 59% Hispanic, 19% Black, 19% White) with 3,406 person-years and a median 3.0 years of follow-up (interquartile range 1.1-4.0 years). Participants with IL-6 levels above the median showed greater cognitive decline on the TICS-m compared to those with levels below the median, adjusting for sociodemographic and vascular factors (β = -0.17 points/year, p = 0.02). Decline on the TICS-m among participants with IL-6 above the median differed by age (p for interaction <0.001). There was no interaction by race/ethnicity, vascular risk factors, C-reactive protein, apolipoprotein ε4 allele status, or the metabolic syndrome among nondiabetics.

CONCLUSIONS

IL-6 associated with cognitive decline among older participants in this racially/ethnically diverse sample independent of other vascular risk factors and C-reactive protein.

Daytime sleepiness and risk of stroke and vascular disease: findings from the Northern Manhattan Study (NOMAS)

BACKGROUND

Recent studies have suggested that poor quality and diminished quantity of sleep may be independently linked to vascular events although prospective and multiethnic studies are limited. This study aimed to explore the relationship between daytime sleepiness and the risk of ischemic stroke and vascular events in an elderly, multiethnic prospective cohort.

METHODS AND RESULTS

As part of the Northern Manhattan Study, the Epworth Sleepiness Scale was collected during the 2004 annual follow-up. Daytime sleepiness was trichotomized using previously reported cut points of no dozing, some dozing, and significant dozing. Subjects were followed annually for a mean of 5.1 years. Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals for stroke, myocardial infarction, and death outcomes. We obtained the Epworth Sleepiness Scale on 2088 community residents. The mean age was 73.5 ± 9.3 years; 64% were women; 17% were white, 20% black, 60% Hispanic, and 3% were other. Over 44% of the cohort reported no daytime dozing, 47% some dozing, and 9% significant daytime dozing. Compared with those reporting no daytime dozing, individuals reporting significant dozing had an increased risk of ischemic stroke (hazard ratio, 2.74 [95% confidence interval, 1.38-5.43]), all stroke (3.00 [1.57-5.73]), the combination of ischemic stroke, myocardial infarction, and vascular death (2.38 [1.50-3.78]), and all vascular events (2.48 [1.57-3.91]), after adjusting for medical comorbidities.

CONCLUSIONS

Daytime sleepiness is an independent risk factor for stroke and other vascular events. These findings suggest the importance of screening for sleep problems at the primary care level.

Trajectory of functional decline before and after ischemic stroke: the Northern Manhattan Study

BACKGROUND AND PURPOSE

Previous research in our cohort showed a delayed decline in functional status after first ischemic stroke. We compared the long-term trajectory of functional status before and after ischemic stroke.

METHODS

The Northern Manhattan Study contains a prospective, population-based study of stroke-free individuals age ≥40 years, followed for a median of 11 years. The Barthel index (BI), a commonly used measure of activities of daily living, was assessed annually. Generalized estimating equations were used to assess functional decline over time before stroke and beginning 6 months after stroke. Follow-up was censored at the time of recurrent stroke.

RESULTS

Among 3298 participants, 210 participants had an ischemic stroke during follow-up and had poststroke BI assessed. Mean age (±SD) was 77±9 years, 38% were men, 52% were Hispanic, 37% had diabetes, and 31% had coronary artery disease. There was no difference in rate of functional decline over time before and after stroke (P=0.51), with a decline of 0.96 BI points per year before stroke (P<0.0001) and 1.24 BI points after stroke (P=0.001). However, when stratified by insurance status, among those with Medicaid or no insurance, in a fully adjusted model, there was a difference in slope before and after stroke (P=0.04), with a decline of 0.58 BI points per year before stroke (P=0.02) and 1.94 BI points after stroke (P=0.001).

CONCLUSIONS

In this large, prospective, population-based study with long-term follow-up, there was a significantly steeper decline in functional status after ischemic stroke compared with before stroke among those with Medicaid or no insurance, after adjusting for confounders.

Abstract 235: Predictors of functional decline over time in an urban population: The Northern Manhattan Study

Background: There is limited data on predictors of long-term functional status in population samples, and even less about the effect of vascular risk factors on function. We hypothesized that functional status would decline over time, and that vascular risk factors would affect function and mediate functional decline.

Methods: The Northern Manhattan Study contains a prospective, population-based study of 3298 stroke-free individuals > 40 years of age, followed for a median of 11 years for vascular events. The Barthel index (BI) was assessed annually and analyzed as a continuous variable on a 100-point scale. Generalized estimating equations models were adjusted for demographic, medical, and social risk factors assessed at baseline. Models were censored and uncensored for stroke and myocardial infarction (MI) occurring during follow-up. Secondarily, motor and non-motor domains of the BI were analyzed separately, and models were stratified by age.

Results: Mean age (standard deviation) was 69.2 (10) years, 37% were male, 52% Hispanic, 22% had diabetes, and 74% hypertension. Among 3298 participants, there were 33556 BI assessments. There was an annual decline of 1.02 BI points (p<0.0001). Predictors of change in BI over time included: age (−0.08 BI points per year; p<0.0001), Hispanic ethnicity (−0.22 per year, compared to white; p=0.016), female sex (−0.30 per year, compared to male; p<0.0001), diabetes (−0.38 per year, compared to non-diabetics; p=0.0002), and depression (−0.26 per year, compared to no depression; p=0.046). Results did not change when stroke and MI were censored. Magnitude and significance of predictors of BI were similar for motor and non-motor domains. The following had a different effect on change in BI in those above the median age (68 years), compared to those less than or equal to the median: age (−0.15 per year vs. −0.03; p for difference <0.0001), female compared to male sex (−0.43 per year vs. −0.15; p=0.049), and depression compared to no depression (−0.64 per year vs. −0.008, p=0.023).

Conclusion: In this large, population-based, multi-ethnic study with long-term follow-up, we found a 1% mean decline in function per year that did not change when the effect of vascular events was excluded by censoring. Vascular risk factors predicted functional decline even in the absence of clinical events. The impact of gender sex and depression was stronger amongst the elderly.

Coronary death and myocardial infarction among Hispanics in the Northern Manhattan Study: exploring the Hispanic paradox

PURPOSE

Prior studies have reported that Hispanics have lower cardiovascular disease (CVD) mortality despite a higher burden of risk factors. We examined whether Hispanic ethnicity was associated with a lower risk of nonfatal myocardial infarction (MI) coronary death (CD) and vascular death.

METHODS

A total of 2671 participants in the Northern Manhattan Study without clinical CVD were prospectively evaluated. Cox models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for the association of race-ethnicity with nonfatal MI, CD, and vascular death after adjusting for demographic and CVD risk factors.

RESULTS

Mean age was 68.8 (10.4) years; 52.8% were Hispanic (88% Caribbean-Hispanic). Hispanics were more likely to have hypertension (73.1% vs. 62.2%, p < .001) and diabetes (22.0% vs. 13.3%, p < .001), and less likely to perform any physical activity (50.1% vs. 69.2%, p < .001) compared to non-Hispanic whites (NHW). During a mean 10 years of follow-up there were 154 nonfatal MIs, 186 CD, and 386 vascular deaths. In fully adjusted models, Hispanics had a lower risk of CD (adjusted HR = 0.36, 95% CI: 0.21-0.60), and vascular death (adjusted HR = 0.62, 95% CI: 0.43-0.89), but not nonfatal MI (adjusted HR = 0.95, 95% CI: 0.56-1.60) when compared to NHW.

CONCLUSIONS

We found a "Hispanic paradox" for coronary and vascular deaths, but not nonfatal MI.

Duration of diabetes and risk of ischemic stroke: the Northern Manhattan Study

BACKGROUND AND PURPOSE

Diabetes increases stroke risk, but whether diabetes status immediately before stroke improves prediction and whether duration is important are less clear. We hypothesized that diabetes duration independently predicts ischemic stroke.

METHODS

Among 3298 stroke-free participants in the Northern Manhattan Study, baseline diabetes and age at diagnosis were determined. Incident diabetes was assessed annually (median, 9 years). Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% CI for incident ischemic stroke using baseline diabetes, diabetes as a time-dependent covariate, and duration of diabetes as a time-varying covariate; models were adjusted for demographic and cardiovascular risk factors.

RESULTS

Mean age was 69 ± 10 years (52% Hispanic, 21% white, and 24% black); 22% had diabetes at baseline and 10% had development of diabetes. There were 244 ischemic strokes, and both baseline diabetes (HR, 2.5; 95% CI, 1.9-3.3) and diabetes considered as a time-dependent covariate (HR, 2.4; 95% CI, 1.8-3.2) were similarly associated with stroke risk. Duration of diabetes was associated with ischemic stroke (adjusted HR, 1.03 per year with diabetes; 95% CI, 1.02-1.04). Compared to nondiabetic participants, those with diabetes for 0 to 5 years (adjusted HR, 1.7; 95% CI, 1.1-2.7), 5 to 10 years (adjusted HR, 1.8; 95% CI, 1.1-3.0), and ≥ 10 years (adjusted HR, 3.2; 95% CI, 2.4-4.5) were at increased risk.

CONCLUSIONS

Duration of diabetes is independently associated with ischemic stroke risk adjusting for risk factors. The risk increases 3% each year, and triples with diabetes ≥ 10 years.

Abstract 2145: The Long-term Trajectory Of Functional Decline Before And After Stroke: The Northern Manhattan Study

Background: Previous research in our population showed a steeper long-term decline in functional status after first ischemic stroke among those with Medicaid or no insurance compared to those with Medicare or private insurance. With only post-stroke data, it was unknown whether these findings were caused by the stroke. We sought to compare the long-term trajectory of functional status before and after ischemic stroke.

Methods: The Northern Manhattan Study contains a prospective, population-based study of stroke-free individuals >40 years of age, followed for a median of 10 years. The Barthel index (BI) was assessed annually. Generalized estimating equations were used to assess functional decline over time before and after stroke. The 6 months after stroke were ignored, since the course of recovery during this period is well documented, and our interest was the long-term course of functional status. Follow-up was censored at the time of recurrent stroke. Sociodemographic and medical risk factors were included and results were stratified by insurance status. Linearity of the curves was evaluated by plotting residuals against time and with a lowess curve.

Results: Among 3298 participants, 261 had an ischemic stroke during follow-up, of which 51 died within 6 months of stroke. Among the remaining 210 participants, mean age at stroke (standard deviation) was 77+9 years, 38% were male, 52% were Hispanic, 37% had diabetes, and 31% had coronary artery disease. There was no difference in functional decline over time before and after stroke (p= 0.51), with a decline of 0.96 BI points per year before stroke (p<.0001) and 1.24 after stroke (p=0.001). However, when stratified by insurance status, among those with Medicaid or no insurance, in a fully adjusted model, there was a difference in slope before and after stroke (p=0.04), with a decline of 0.58 BI points per year before stroke (p=0.02) and 1.94 after stroke (p=0.001). Other predictors of worse functional status were increasing age, female sex, diabetes, and being married.

Conclusion: In this large, prospective, population-based study with long-term follow-up, there was a significantly steeper decline in functional status after ischemic stroke compared to before stroke among those with Medicaid or no insurance, after adjusting for confounders. The cause of this differential decline is not known but may be related to poor control of risk factors, silent strokes, or an effect of socioeconomic status.

Abstract 2552: Lipoprotein-associated phospholipase A2 predicts atherosclerotic stroke risk: The Northern Manhattan Study

Background: Lipoprotein-associated phospholipase A2 (Lp-PLA2) has pro-inflammatory properties and may contribute to atherosclerosis, plaque rupture, and stroke. Lp-PLA2 levels may improve risk stratification, though whether this ability extends to all populations and stroke subtypes remains uncertain. We hypothesized that Lp-PLA2 levels would predict first ischemic stroke in a multiethnic, urban, population.

Methods: Serum samples from stroke-free community participants in the Northern Manhattan Study were assayed using a microplate based ELISA to measure the mass concentration of Lp-PLA2 (PLAC Test, diaDexus, Inc). Participants were followed annually for stroke, and stroke subtype was determined according to the TOAST criteria. Cox proportional hazard models were fitted to estimate hazard ratios and 95% confidence intervals (HR, 95% CI) for the association of Lp-PLA2 mass levels with ischemic stroke, unadjusted and after adjusting for demographic, behavioral and medical risk factors.

Results: Serum samples were available in 1946 participants with median follow up of 11 years; 151 subjects (7.8%) experienced a first ischemic stroke, of which 26 were large artery atherosclerotic strokes. Mean age was 69 (SD 10), 35.6% were men, 20% non-Hispanic Whites, 22% Blacks, and 55% Hispanics. The mean Lp-PLA2 level was 308.7 (SD 88.5) ng/mL. In non-Hispanic Whites, there was a trend toward increased risk of ischemic stroke with Lp-PLA2 levels (adjusted HR per SD 1.44, 95% CI 0.98-2.11), but not in Blacks (p for interaction with white=0.045); or in Hispanics (p for interaction with white=0.13). Lp-PLA2 levels were predictive of large artery atherosclerotic strokes (LAA) in the entire cohort (adjusted HR per SD 1.55, 95% CI 1.17-2.04). When analyzed by quartile, there were dose-response relationship with LAA (compared to the lowest quartile, 2nd quartile HR= 1.43, 95% CI 0.23-8.64; 3rd quartile HR=4.47, 95% CI 0.93-21.54; 4th quartile HR=5.07, 95% CI 1.07-24.06). When the analysis was stratified by race, Lp-PLA2 was associated with increased risk of LAA among whites, but not blacks or Hispanics (chi-squared 2 degrees of freedom, p for interaction=0.01).

Conclusion: Lp-PLA2 was associated with risk of atherosclerotic stroke among non-Hispanic White participants, but not in other race-ethnic groups in the cohort. Further study is needed to confirm these race-ethnic differences and the reasons for them.

Abstract P48: The Inclusion of Stroke in Risk Stratification for Primary Prevention of Vascular Events: the Northern Manhattan Study

Background: The Framingham coronary heart disease risk score (FRS) estimates 10-year risk of myocardial infarction (MI) and coronary heart disease (CHD) death and is used to risk stratify individuals for vascular disease primary prevention. Since the preventive approaches to CHD and stroke are similar, a composite outcome may be more appropriate, and estimating risk of cardiac events alone may underestimate risk. We compared 10-year risk of MI or CHD death to risk of stroke, MI, or CHD death among individuals free of vascular disease, focusing on those with intermediate calculated FRS risk (10-20% over 10 years). We also used the Framingham general cardiovascular disease score (FGS), which calculates risk of a composite vascular outcome, but for which guidelines do not exist.

Methods: The Northern Manhattan Study contains a prospective, population-based study of stroke- and CHD-free individuals ≥40 years of age, followed for a median of 10 years for MI, CHD death, and stroke. The FRS was used to calculate estimated 10-year risk of MI or CHD death. For those with intermediate estimated risk, Kaplan-Meier actual 10-year risks were calculated for 1) MI or CHD death and 2) stroke, MI, or CHD death. The cumulative risk of MI or CHD death was subtracted from risk of stroke, MI, or CHD death, and bootstrap methods produced 95% confidence intervals (CI) for the difference. This analysis was repeated using the FGS to stratify risk.

Results: Among 2613 participants (53% Hispanic, 25% non Hispanic Black and 20% non Hispanic White), 867 had 10-20% estimated 10-year FRS risk. The actual 10-year risk of MI or CHD death was 14.2%. When stroke was added to the outcome, actual risk was 21.98% (absolute risk difference 7.78, 95% CI 5.86-9.75). For those with intermediate FGS risk, actual 10-year risk of MI or CHD death was 6.5. When stroke was added, actual risk was 10.55 (absolute difference 4.05, 95% CI 2.63-5.85).

Discussion: In this multi-ethnic urban population, adding stroke to the risk stratification outcome cluster resulted in a 55% increase in risk and crossing of the threshold (>20% over 10 years) considered for preventive treatments such as statins. Research is needed to clarify the optimal use of primary risk stratification schemes, particularly among minority populations.

The metabolic syndrome and cognitive performance: the Northern Manhattan Study

BACKGROUND

The metabolic syndrome (MetS) is a risk factor for diabetes, stroke, myocardial infarction, and increased mortality, and has been associated with cognition in some populations. We hypothesized that MetS would be associated with lower Mini-Mental State Examination (MMSE) scores in a multi-ethnic population, and that MetS is a better predictor of cognition than its individual components or diabetes.

METHODS

We conducted a cross-sectional analysis among 3,150 stroke-free participants. MetS was defined by the modified National Cholesterol Education Program guidelines-Adult Treatment Panel III (NCEP-ATPIII) criteria. Linear regression and polytomous logistic regression estimated the association between MMSE score and MetS, its individual components, diabetes, and inflammatory biomarkers.

RESULTS

MetS was inversely associated with MMSE score (unadjusted β = -0.67; 95% CI -0.92, -0.41). Adjusting for potential confounders, MetS was associated with lower MMSE score (adjusted β = -0.24; 95% CI -0.47, -0.01), but its individual components and diabetes were not. Those with MetS were more likely to have an MMSE score of <18 than a score of ≥ 24 (adjusted OR = 1.94; 95% CI 1.26, 3.01). There was an interaction between MetS and race-ethnicity, such that MetS was associated with lower MMSE score among non-Hispanic whites and Hispanics but not non-Hispanic blacks.

CONCLUSIONS

MetS was associated with lower cognition in a multi-ethnic population. Further studies of the effect of MetS on cognition are warranted, and should account for demographic differences.

Perception of recurrent stroke risk among black, white and Hispanic ischemic stroke and transient ischemic attack survivors: the SWIFT study

OBJECTIVES

Risk modification through behavior change is critical for primary and secondary stroke prevention. Theories of health behavior identify perceived risk as an important component to facilitate behavior change; however, little is known about perceived risk of vascular events among stroke survivors.

METHODS

The SWIFT (Stroke Warning Information and Faster Treatment) study includes a prospective population-based ethnically diverse cohort of ischemic stroke and transient ischemic attack survivors. We investigate the baseline relationship between demographics, health beliefs, and knowledge on risk perception. Regression models examined predictors of inaccurate perception.

RESULTS

Only 20% accurately estimated risk, 10% of the participants underestimated risk, and 70% of the 817 study participants significantly overestimated their risk for a recurrent stroke. The mean perceived likelihood of recurrent ischemic stroke in the next 10 years was 51 ± 7%. We found no significant differences by race-ethnicity with regard to accurate estimation of risk. Inaccurate estimation of risk was associated with attitudes and beliefs [worry (p < 0.04), fatalism (p < 0.07)] and memory problems (p < 0.01), but not history or knowledge of vascular risk factors.

CONCLUSION

This paper provides a unique perspective on how factors such as belief systems influence risk perception in a diverse population at high stroke risk. There is a need for future research on how risk perception can inform primary and secondary stroke prevention.

Social network types and acute stroke preparedness behavior

Objectives

Presence of informal social networks has been associated with favorable health and behaviors, but whether different types of social networks impact on different health outcomes remains largely unknown. We examined the associations of different social network types (marital dyad, household, friendship, and informal community networks) with acute stroke preparedness behavior. We hypothesized that marital dyad best matched the required tasks and is the most effective network type for this behavior.

Methods

We collected in-person interview and medical record data for 1,077 adults diagnosed with stroke and transient ischemic attack. We used logistic regression analyses to examine the association of each social network with arrival at the emergency department (ED) within 3 h of stroke symptoms.

Results

Adjusting for age, race-ethnicity, education, gender, transportation type to ED and vascular diagnosis, being married or living with a partner was significantly associated with early arrival at the ED (odds ratio = 2.0, 95% confidence interval: 1.2–3.1), but no significant univariate or multivariate associations were observed for household, friendship, and community networks.

Conclusions

The marital/partnership dyad is the most influential type of social network for stroke preparedness behavior.

The inclusion of stroke in risk stratification for primary prevention of vascular events: the Northern Manhattan Study

BACKGROUND AND PURPOSE

The Framingham coronary heart disease (CHD) risk score estimates 10-year risk of myocardial infarction (MI) and CHD death. Because preventive approaches to CHD and stroke are similar, a composite outcome may be more appropriate. We compared 10-year risk of (1) MI or CHD death; and (2) stroke, MI, or CHD death among individuals free of vascular disease.

METHODS

The Northern Manhattan Study contains a prospective, population-based study of stroke- and CHD-free individuals≥40 years of age followed for a median of 10 years for vascular events. Framingham coronary heart disease risk score was calculated for each individual and for each category of predicted risk, Kaplan-Meier observed 10-year cumulative probabilities were calculated for (1) MI or CHD death; and (2) stroke, MI, or CHD death. The cumulative probability of (1) was subtracted from (2), and 95% CIs for the difference were obtained with 1000 bootstrap samples. Using stratified analyses by race-ethnicity, we compared risk differences among race-ethnic groups.

RESULTS

Among 2613 participants (53% Hispanic, 25% non-Hispanic black, and 20% non-Hispanic white), observed 10-year risk of MI or CHD death was 14.20%. With stroke in the outcome, observed risk was 21.98% (absolute risk difference, 7.78%; 95% CI, 5.86% to 9.75%). The absolute risk difference among blacks was significantly larger than among whites (P=0.01).

CONCLUSIONS

In this multiethnic urban population, adding stroke to the risk stratification outcome cluster resulted in a 55% relative increase in estimated risk and crossing of the absolute risk threshold (>20% over 10 years) considered for preventive treatments such as statins.

Lower prevalence of silent brain infarcts in the physically active: the Northern Manhattan Study

OBJECTIVE

To examine the independent association between physical activity and subclinical cerebrovascular disease as measured by silent brain infarcts (SBI) and white matter hyperintensity volume (WMHV).

METHODS

The Northern Manhattan Study (NOMAS) is a population-based prospective cohort examining risk factors for incident vascular disease, and a subsample underwent brain MRI. Our primary outcomes were SBI and WMHV. Baseline measures of leisure-time physical activity were collected in person. Physical activity was categorized by quartiles of the metabolic equivalent (MET) score. We used logistic regression models to examine the associations between physical activity and SBI, and linear regression to examine the association with WMHV.

RESULTS

There were 1,238 clinically stroke-free participants (mean age 70 ± 9 years) of whom 60% were women, 65% were Hispanic, and 43% reported no physical activity. A total of 197 (16%) participants had SBI. In fully adjusted models, compared to those who did not engage in physical activity, those in the upper quartile of MET scores were almost half as likely to have SBI (adjusted odds ratio 0.6, 95% confidence interval 0.4-0.9). Physical activity was not associated with WMHV.

CONCLUSIONS

Increased levels of physical activity were associated with a lower risk of SBI but not WMHV. Engaging in moderate to heavy physical activities may be an important component of prevention strategies aimed at reducing subclinical brain infarcts.

Race-ethnic differences in the association between lipid profile components and risk of myocardial infarction: The Northern Manhattan Study

OBJECTIVE

The aim of this study was to explore race-ethnic differences in the association between plasma lipid components and risk of incident myocardial infarction (MI).

DESIGN/METHODS

As part of the Northern Manhattan Study, 2,738 community residents without cardiovascular disease were prospectively evaluated. Baseline fasting blood samples were collected, and lipid panel components were analyzed as continuous and categorical variables. Cox proportional hazards models were used to calculate HRs and 95% CIs for incident MI after adjusting for demographic and cardiovascular risk factors.

RESULTS

The mean age was 68.8 ± 10.4 years; 36.7% were men. Of the participants, 19.9% were non-Hispanic white; 24.9%, non-Hispanic black; and 52.8%, Hispanic (>80% from the Caribbean). Hispanics had lower mean high-density lipoprotein cholesterol (HDL-C) and higher triglycerides (TG)/HDL-C. During a mean 8.9 years of follow-up, there were 163 incident MIs. In the whole cohort, all lipid profile components were associated with risk of MI in the expected directions. However, HDL-C (adjusted HR per 10 mg/dL increase 0.93, 95% CI 0.76-1.12) and TG/HDL-C >2 (adjusted HR 0.89, 95% CI 0.51-1.55) were not predictive of MI among Hispanics but were predictive among non-Hispanic blacks and whites. Triglycerides/HDL-C per unit increase was associated with an 8% higher risk of MI among Hispanics (adjusted HR 1.08, 95% CI 1.04-1.12).

CONCLUSIONS

In Hispanics, low HDL-C and TG/HDL-C >2 were not associated with MI risk. Our data suggest that a different TG/HDL ratio cutoff may be needed among Hispanics to predict MI risk.

Social determinants of physical inactivity in the Northern Manhattan Study (NOMAS)

Physical inactivity is an important and modifiable cardiovascular disease risk factor. Little is known about the social determinants of physical inactivity in older, urban-dwelling populations. We collected socio-demographic and medical risk factor information and physical activity questionnaires in the Northern Manhattan Study. Logistic regression models were constructed to examine whether measures of social isolation, race-ethnicity, and sex were associated with physical inactivity. Physical inactivity was present in 40.5% of the cohort. In multivariable models adjusted for medical comorbidities, Hispanic race-ethnicity (compared to non-Hispanic white) was associated with higher odds of physical inactivity (OR 2.18, 95% CI 1.78, 2.67), while women were more likely to be inactive than men (OR 1.33, 95% CI 1.15, 1.54). Having Medicaid/being uninsured (OR 1.20, 95% CI 1.02, 1.42), and having fewer than 3 friends (1.41, 95% CI 1.15, 1.72) were also associated with physical inactivity. Physical inactivity is common, particularly in Hispanics, women, and those who are socially isolated. Public health interventions aimed at increasing physical activity in these more sedentary groups are required.

Association of serum soluble receptor for advanced glycation end-products with subclinical cerebrovascular disease: the Northern Manhattan Study (NOMAS)

OBJECTIVE

Serum levels of the soluble receptor for advanced glycation end-products (sRAGE) have been associated with risk of cardiovascular disease. We hypothesized that sRAGE levels are associated with subclinical cerebrovascular disease in an ethnically diverse population.

METHODS

Clinically stroke-free participants in the multi-ethnic Northern Manhattan Study (NOMAS) underwent brain MRI to quantify subclinical brain infarcts (SBI) and white matter hyperintensity volume (WMHV) (n = 1102). Serum levels of sRAGE were measured by ELISA. Logistic and multiple linear regression were employed to estimate associations of sRAGE with SBI and WMHV, after adjusting for demographics and vascular risk factors.

RESULTS

Median sRAGE levels were significantly lower in Hispanics (891.9 pg/ml; n = 708) and non-Hispanic blacks (757.4 pg/ml; n = 197) than in non-Hispanic whites (1120.5 pg/ml; n = 170), and these differences remained after adjusting for other risk factors. Interactions were observed by race-ethnicity between sRAGE levels and MRI measurements, including for SBI in Hispanics (p = 0.04) and WMHV among blacks (p = 0.03). In Hispanics, increasing sRAGE levels were associated with a lower odds of SBI, with those in the upper sRAGE quartile displaying a 50% lower odds of SBI after adjusting for sociodemographic and vascular risk factors (p = 0.05). Among blacks, those in the upper quartile of sRAGE had a similarly reduced increased risk of SBI (p = 0.06) and greater WMHV (p = 0.04).

CONCLUSION

Compared to whites, Hispanics and blacks have significantly lower sRAGE levels, and these levels were associated with more subclinical brain disease. Taken together, these findings suggest sRAGE levels may be significantly influence by ethnicity. Further studies of sRAGE and stroke risk, particularly in minorities, are warranted.

Insulin resistance and risk of ischemic stroke among nondiabetic individuals from the northern Manhattan study

BACKGROUND

Whether insulin resistance predicts ischemic stroke (IS) is still a matter of debate.

OBJECTIVE

To determine the association between insulin resistance (IR) and risk of first ischemic stroke in a large, multiethnic, stroke-free cohort without diabetes.

DESIGN

Prospective, population-based cohort study.

SETTING

Longitudinal epidemiologic study.

PARTICIPANTS

A cohort of 1509 nondiabetic participants from the Northern Manhattan Study (mean [SD] age, 11 [10] years; 64.2% women; 58.9% Hispanics).

MAIN OUTCOME MEASURES

Insulin sensitivity, expressed by the homeostasis model assessment (HOMA) of insulin sensitivity (HOMA index = [fasting insulin × fasting glucose] / 22.5). Insulin resistance was defined by a HOMA-IR index in the top quartile (Q4). Cox proportional hazards models were used to determine the effect of HOMA-IR on the risk of incident IS, myocardial infarction (MI), vascular death, and combined outcomes (IS, MI, and vascular death).

RESULTS

The mean (SD) HOMA-IR was 2.3 (2.1), and Q4 was at least 2.8. During mean follow-up of 8.5 years, vascular events occurred in 180 participants; 46 had fatal or nonfatal IS, 45 had fatal or nonfatal MI, and 121 died of vascular causes. The HOMA-IR Q4 vs less than Q4 significantly predicted the risk of IS only (adjusted hazard ratio, 2.83; 95% confidence interval, 1.34-5.99) but not other vascular events. This effect was independent of sex, race/ethnicity, traditional vascular risk factors, and metabolic syndrome and its components.

CONCLUSIONS

Insulin resistance estimated using the HOMA is a marker of increased risk of incident stroke in nondiabetic individuals. These findings emphasize the need to better characterize individuals at increased risk for IS and the potential role of primary preventive therapies targeted at IR.

Metabolic syndrome increases carotid artery stiffness: the Northern Manhattan Study

BACKGROUND

Arterial stiffness, an intermediate pre-clinical marker of atherosclerosis, has been associated with an increased risk of stroke and cardiovascular disease. The metabolic syndrome and its components are established cardiovascular disease risk factors and may also increase arterial stiffness; however, data regarding this are limited.

AIM

The goal of this study was to determine the association between the metabolic syndrome and carotid artery stiffness in an elderly multi-ethnic cohort.

METHODS

Carotid artery stiffness was assessed by carotid ultrasound as part of the Northern Manhattan Study, a prospective population-based cohort of stroke-free individuals. Carotid artery stiffness was calculated as [ln(systolic BP/diastolic BP)/strain], where strain was [(systolic diameter-diastolic diameter)/diastolic diameter]. Metabolic syndrome was defined by the National Cholesterol Education Program: Adult Treatment Panel III criteria. LogSTIFF was analysed as the dependent variable in linear regression models, adjusting for demographics, education, current smoking, presence of carotid plaque and intima-media thickness.

RESULTS

Carotid artery stiffness was analysed in 1133 Northern Manhattan Study subjects (mean age 65 +/- 9 years; 61% women; 58% Hispanic, 22% Black and 20% Caucasian). The prevalence of the metabolic syndrome was 49%. The mean LogSTIFF was 2.01 +/- 0.61 among those with the metabolic syndrome and 1.90 +/- 0.59 among those without the metabolic syndrome (P=0.003). The metabolic syndrome was significantly associated with increased logSTIFF in the final adjusted model (parameter estimate beta=0.100, P=0.01). Among individual metabolic syndrome components, waist circumference and elevated blood pressure were most significantly associated with a mean increase in logSTIFF (P<0.01).

CONCLUSION

The metabolic syndrome is significantly associated with increased carotid artery stiffness in a multiethnic population. Increased carotid artery stiffness may, in part, explain a high risk of stroke among individuals with the metabolic syndrome.

The Levels of Inflammatory Markers in the Treatment of Stroke study (LIMITS): inflammatory biomarkers as risk predictors after lacunar stroke

BACKGROUND

Inflammation is increasingly recognised as playing a central role in atherosclerosis, and peripheral blood markers of inflammation have been associated with incident and recurrent cardiac events. The relationship of these potentially modifiable risk markers to prognosis after ischaemic stroke is less clear. The Levels of Inflammatory Markers in the Treatment of Stroke (LIMITS) study will address hypotheses related to the role of inflammatory markers in secondary stroke prevention in an efficient manner using the well-established framework of the Secondary Prevention of Small Subcortical Strokes (SPS3) trial (NCT00059306).

METHODS

SPS3 is an ongoing Phase III multicentre secondary prevention trial focused on preventing recurrent stroke in patients with small vessel ischaemic stroke, or lacunes. In SPS3, patients are assigned in a factorial design to aspirin vs. aspirin plus clopidogrel, and to usual vs. aggressive blood pressure targets. The purpose of LIMITS is to determine whether serum levels of inflammatory markers - including high-sensitivity C-reactive protein, serum amyloid A, CD40 ligand, and monocyte chemoattractant protein-1 - predict recurrent stroke and other vascular events among lacunar stroke patients. The project will also determine whether these markers predict which people will respond best to dual antiplatelet therapy with clopidogrel and aspirin, as well the relationship to cognitive function.

ANALYSIS

plan Multivariable Cox proportional hazard regression modeling will be used to estimate hazard ratios for the effect of marker levels on risk of recurrent stroke and other outcomes after adjusting for additional potential risk factors, including age, gender, ethnicity, treatment arm, and traditional stroke risk factors. Interactions between marker levels and treatment assignment for both arms of the SPS3 study will be assessed. Observations will be censored at the time of last follow-up visit.

CONCLUSIONS

LIMITS represents an efficient approach to the identification of novel inflammatory biomarkers for use in risk prediction and treatment selection in patients with small vessel disease.

Early depressed mood after stroke predicts long-term disability: the Northern Manhattan Stroke Study (NOMASS)

BACKGROUND AND PURPOSE

Depression is highly prevalent after stroke and may influence recovery. We aimed to determine whether depressed mood acutely after stroke predicts subsequent disability and mortality.

METHODS

As part of the Northern Manhattan Stroke Study, a population-based incident stroke case follow-up study performed in a multiethnic urban population, participants were asked about depressed mood within 7 to 10 days after stroke. Participants were followed every 6 months the first 2 years and yearly thereafter for 5 years for death and disability measured by the Barthel Index. We fitted polytomous logistic regression models using a canonical link to examine the association between depressed mood after stroke and disability comparing moderate (Barthel Index 60 to 95) and severe (Barthel Index <60) disability with no disability (Barthel Index >or=95). Cox proportional hazards models were created to examine the association between depressed mood and mortality.

RESULTS

A question about depressed mood within 7 to 10 days after stroke was asked in 340 of 655 patients with ischemic stroke enrolled, and 139 reported that they felt depressed. In multivariate analyses controlling for sociodemographic factors, stroke severity, and medical conditions, depressed mood was associated with a greater odds of severe disability compared with no disability at 1 (OR 2.91, 95% CI 1.07 to 7.91) and 2 years (OR 3.72, 95% CI 1.29 to 10.71) after stroke. Depressed mood was not associated with all-cause mortality or vascular death.

CONCLUSIONS

Depressed mood after stroke is associated with disability but not mortality after stroke. Early screening and intervention for mood disorders after stroke may improve outcomes and requires further research.

Increased stroke risk and lipoprotein(a) in a multiethnic community: the Northern Manhattan Stroke Study

CONTEXT

Elevated lipoprotein(a) [Lp(a)] is associated with ischemic stroke (IS) among Whites, but data is sparse for non-White populations.

OBJECTIVE

Using a population-based case-control study design with subjects from the Northern Manhattan Stroke Study, we assessed whether Lp(a) levels were independently associated with IS risk among Whites, Blacks and Hispanics.

DESIGN AND SETTING

Lp(a) levels were measured in 317 IS cases (mean age 69 +/- 13 years; 56% women; 16% Whites, 31% Blacks and 52% Hispanics) and 413 community-based controls, matched by age, race/ethnicity and gender. In-person assessments included demographics, socioeconomic status, presence of vascular risk factors and fasting lipid levels. Logistic regression was used to determine the independent association of Lp(a) and IS. Stratified analyses investigated gender and race/ethnic differences.

RESULTS

Mean Lp(a) levels were greater among cases than controls (46.3 +/- 41.0 vs. 38.9 +/- 38.2 mg/dl; p < 0.01). After adjusting for stroke risk factors (hypertension, diabetes mellitus, coronary artery disease, cigarette smoking), lipid levels, and socioeconomic status, Lp(a) levels > or =30 mg/dl were independently associated with an increased stroke risk in the overall cohort (adjusted odds ratio, OR, 1.8, 95% confidence interval, CI, 1.20-2.6; p = 0.004). There was a significant linear dose-response relationship between Lp(a) levels and IS risk. The association between IS risk and Lp(a) > or =30 mg/dl was more pronounced among men (adjusted OR 2.0, 95% CI 1.1-3.5; p = 0.02) and among Blacks (adjusted OR 2.7, 95% CI 1.2-6.2; p = 0.02).

CONCLUSION

Elevated Lp(a) levels were significantly and independently associated with increased stroke risk, suggesting that Lp(a) is a risk factor for IS across White, Black and Hispanic race/ethnic groups.

Quality of life declines after first ischemic stroke. The Northern Manhattan Study

OBJECTIVES

Quality of life (QOL) after stroke is poorly characterized. We sought to determine long-term natural history and predictors of QOL among first ischemic stroke survivors without stroke recurrence or myocardial infarction (MI).

METHODS

In the population-based, multiethnic Northern Manhattan Study, QOL was prospectively assessed at 6 months and annually for 5 years using the Spitzer QOL index (QLI), a 10-point scale. Functional status was assessed using the Barthel Index (BI) at regular intervals, and cognition using the Mini-Mental State Examination at 1 year. Generalized estimating equations estimated the association between patient characteristics and repeated QOL measures over 5 years. Follow-up was censored at death, recurrent stroke, or MI.

RESULTS

There were 525 incident ischemic stroke patients >/=40 years (mean age 68.6 +/- 12.4 years). QLI declined after stroke (annual change -0.10, 95% confidence interval -0.17 to -0.04), after adjusting for age, sex, race-ethnicity, education, insurance, depressed mood, stroke severity, bladder continence, and stroke laterality. This decline remained when BI >/=95 was added to the model as a time-dependent covariate, and functional status also predicted QLI. Changes in QLI over time differed by insurance status (p for interaction = 0.0017), with a decline for those with Medicaid/no insurance (p < 0.0001) but not Medicare/private insurance (p = 0.98).

CONCLUSIONS

In this population-based study, QOL declined annually up to 5 years after stroke among survivors free of recurrence or MI and independently of other risk factors. QLI declined more among Medicaid patients and was associated with age, mood, stroke severity, urinary incontinence, functional status, cognition, and stroke laterality.

Infectious burden and carotid plaque thickness: the northern Manhattan study

BACKGROUND AND PURPOSE

The overall burden of prior infections may contribute to atherosclerosis and stroke risk. We hypothesized that serological evidence of common infections would be associated with carotid plaque thickness in a multiethnic cohort.

METHODS

Antibody titers to 5 common infectious microorganisms (ie, Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpesvirus 1 and 2) were measured among stroke-free community participants and a weighted index of infectious burden was calculated based on Cox models previously derived for the association of each infection with stroke risk. High-resolution carotid duplex Doppler studies were used to assess maximum carotid plaque thickness. Weighted least squares regression was used to measure the association between infectious burden and maximum carotid plaque thickness after adjusting for other risk factors.

RESULTS

Serological results for all 5 infectious organisms were available in 861 participants with maximum carotid plaque thickness measurements available (mean age, 67.2+/-9.6 years). Each individual infection was associated with stroke risk after adjusting for other risk factors. The infectious burden index (n=861) had a mean of 1.00+/-0.35 SD and a median of 1.08. Plaque was present in 52% of participants (mean, 0.90+/-1.04 mm). Infectious burden was associated with maximum carotid plaque thickness (adjusted increase in maximum carotid plaque thickness 0.09 mm; 95% CI, 0.03 to 0.15 mm per SD increase of infectious burden).

CONCLUSIONS

A quantitative weighted index of infectious burden, derived from the magnitude of association of individual infections with stroke, was associated with carotid plaque thickness in this multiethnic cohort. These results lend support to the notion that past or chronic exposure to common infections, perhaps by exacerbating inflammation, contributes to atherosclerosis. Future studies are needed to confirm this hypothesis and to define optimal measures of infectious burden as a vascular risk factor.

Infectious burden and carotid plaque thickness: the northern Manhattan study

BACKGROUND AND PURPOSE

The overall burden of prior infections may contribute to atherosclerosis and stroke risk. We hypothesized that serological evidence of common infections would be associated with carotid plaque thickness in a multiethnic cohort.

METHODS

Antibody titers to 5 common infectious microorganisms (ie, Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpesvirus 1 and 2) were measured among stroke-free community participants and a weighted index of infectious burden was calculated based on Cox models previously derived for the association of each infection with stroke risk. High-resolution carotid duplex Doppler studies were used to assess maximum carotid plaque thickness. Weighted least squares regression was used to measure the association between infectious burden and maximum carotid plaque thickness after adjusting for other risk factors.

RESULTS

Serological results for all 5 infectious organisms were available in 861 participants with maximum carotid plaque thickness measurements available (mean age, 67.2+/-9.6 years). Each individual infection was associated with stroke risk after adjusting for other risk factors. The infectious burden index (n=861) had a mean of 1.00+/-0.35 SD and a median of 1.08. Plaque was present in 52% of participants (mean, 0.90+/-1.04 mm). Infectious burden was associated with maximum carotid plaque thickness (adjusted increase in maximum carotid plaque thickness 0.09 mm; 95% CI, 0.03 to 0.15 mm per SD increase of infectious burden).

CONCLUSIONS

A quantitative weighted index of infectious burden, derived from the magnitude of association of individual infections with stroke, was associated with carotid plaque thickness in this multiethnic cohort. These results lend support to the notion that past or chronic exposure to common infections, perhaps by exacerbating inflammation, contributes to atherosclerosis. Future studies are needed to confirm this hypothesis and to define optimal measures of infectious burden as a vascular risk factor.

Lipid profile components and risk of ischemic stroke: the Northern Manhattan Study (NOMAS)

OBJECTIVE

To explore the relationship between lipid profile components and incident ischemic stroke in a stroke-free prospective cohort.

DESIGN

Population-based prospective cohort study.

SETTING

Northern Manhattan, New York.

PATIENTS

Stroke-free community residents. Intervention As part of the Northern Manhattan Study, baseline fasting blood samples were collected on stroke-free community residents followed up for a mean of 7.5 years.

MAIN OUTCOME MEASURES

Cox proportional hazard models were used to calculate hazard ratios and 95% confidence intervals for lipid profile components and ischemic stroke after adjusting for demographic and risk factors. In secondary analyses, we used repeated lipid measures over 5 years from a 10% sample of the population to calculate the change per year of each of the lipid parameters and to impute time-dependent lipid parameters for the full cohort.

RESULTS

After excluding those with a history of myocardial infarction, 2940 participants were available for analysis. Baseline high-density lipoprotein cholesterol, triglyceride, and total cholesterol levels were not associated with risk of ischemic stroke. Low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol levels were associated with a paradoxical reduction in risk of stroke. There was an interaction with use of cholesterol-lowering medication on follow-up, such that LDL-C level was only associated with a reduction in stroke risk among those taking medications. An LDL-C level greater than 130 mg/dL as a time-dependent covariate showed an increased risk of ischemic stroke (adjusted hazard ratio, 3.81; 95% confidence interval, 1.53-9.51).

CONCLUSIONS

Baseline lipid panel components were not associated with an increased stroke risk in this cohort. Treatment with cholesterol-lowering medications and changes in LDL-C level over time may have attenuated the risk in this population, and lipid measurements at several points may be a better marker of stroke risk.

Physical activity and risk of ischemic stroke in the Northern Manhattan Study

BACKGROUND

It is controversial whether physical activity is protective against first stroke among older persons. We sought to examine whether physical activity, as measured by intensity of exercise and energy expended, is protective against ischemic stroke.

METHODS

The Northern Manhattan Study is a prospective cohort study in older, urban-dwelling, multiethnic, stroke-free individuals. Baseline measures of leisure-time physical activity were collected via in-person questionnaires. Cox proportional hazards models were constructed to examine whether energy expended and intensity of physical activity were associated with the risk of incident ischemic stroke.

RESULTS

Physical inactivity was present in 40.5% of the cohort. Over a median follow-up of 9.1 years, there were 238 incident ischemic strokes. Moderate- to heavy-intensity physical activity was associated with a lower risk of ischemic stroke (adjusted hazard ratio [HR] 0.65, 95% confidence interval [0.44-0.98]). Engaging in any physical activity vs none (adjusted HR 1.16, 95% CI 0.88-1.51) and energy expended in kcal/wk (adjusted HR per 500-unit increase 1.01, 95% CI 0.99-1.03) were not associated with ischemic stroke risk. There was an interaction of sex with intensity of physical activity (p = 0.04), such that moderate to heavy activity was protective against ischemic stroke in men (adjusted HR 0.37, 95% CI 0.18-0.78), but not in women (adjusted HR 0.92, 95% CI 0.57-1.50).

CONCLUSIONS

Moderate- to heavy-intensity physical activity, but not energy expended, is protective against risk of ischemic stroke independent of other stroke risk factors in men in our cohort. Engaging in moderate to heavy physical activities may be an important component of primary prevention strategies aimed at reducing stroke risk.

Improving global vascular risk prediction with behavioral and anthropometric factors. The multiethnic NOMAS (Northern Manhattan Cohort Study)

OBJECTIVES

This study sought to improve global vascular risk prediction with behavioral and anthropometric factors.

BACKGROUND

Few cardiovascular risk models are designed to predict the global vascular risk of myocardial infarction, stroke, or vascular death in multiethnic individuals, and existing schemes do not fully include behavioral risk factors.

METHODS

A randomly derived, population-based, prospective cohort of 2,737 community participants free of stroke and coronary artery disease was followed up annually for a median of 9.0 years in the NOMAS (Northern Manhattan Study) (mean age 69 years, 63.2% women, 52.7% Hispanic, 24.9% African American, and 19.9% white). A global vascular risk score (GVRS) predictive of stroke, myocardial infarction, or vascular death was developed by adding variables to the traditional Framingham cardiovascular variables based on the likelihood ratio criteria. Model utility was assessed through receiver-operating characteristics, calibration, and effect on reclassification of subjects.

RESULTS

Variables that significantly added to the traditional Framingham profile included waist circumference, alcohol consumption, and physical activity. Continuous measures for blood pressure and fasting blood sugar were used instead of hypertension and diabetes. Ten-year event-free probabilities were 0.95 for the first quartile of GVRS, 0.89 for the second quartile, 0.79 for the third quartile, and 0.56 for the fourth quartile. The addition of behavioral factors in our model improved prediction of 10-year event rates compared with a model restricted to the traditional variables.

CONCLUSIONS

A GVRS that combines traditional, behavioral, and anthropometric risk factors; uses continuous variables for physiological parameters; and is applicable to nonwhite subjects could improve primary prevention strategies.

High-sensitivity C-reactive protein predicts mortality but not stroke: the Northern Manhattan Study

OBJECTIVE

To determine whether high-sensitivity C-reactive protein (hsCRP) and serum amyloid A (SAA) predict stroke, vascular events, and mortality in a prospective cohort study.

BACKGROUND

Markers of inflammation have been associated with risk of myocardial infarction (MI). Their association with stroke is controversial.

METHODS

The Northern Manhattan Study includes a stroke-free community-based cohort study in participants aged > or =40 years (median follow-up 7.9 years). hsCRP and SAA were measured using nephelometry. Cox proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for the association of markers with risk of ischemic stroke and other outcomes after adjusting for demographics and risk factors.

RESULTS

hsCRP measurements were available in 2,240 participants (mean age 68.9 +/- 10.1 years; 64.2% women; 18.8% white, 23.5% black, and 55.1% Hispanic). The median hsCRP was 2.5 mg/L. Compared with those with hsCRP <1 mg/L, those with hsCRP >3 mg/L were at increased risk of ischemic stroke in a model adjusted for demographics (HR = 1.60, 95% CI 1.06-2.41), but the effect was attenuated after adjusting for other risk factors (adjusted HR = 1.20, 95% CI 0.78-1.86). hsCRP >3 mg/L was associated with risk of MI (adjusted HR = 1.70, 95% CI 1.04-2.77) and death (adjusted HR = 1.55, 95% CI 1.23-1.96). SAA was not associated with stroke risk.

CONCLUSION

In this multiethnic cohort, high-sensitivity C-reactive protein (hsCRP) was not associated with ischemic stroke, but was modestly associated with myocardial infarction and mortality. The value of hsCRP and serum amyloid A may depend on population characteristics such as age and other risk factors.

Infectious burden and risk of stroke: the northern Manhattan study

OBJECTIVE

To determine the association between a composite measure of serological test results for common infections (Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpes simplex virus 1 and 2) and stroke risk in a prospective cohort study.

DESIGN

Prospective cohort followed up longitudinally for median 8 years.

SETTING

Northern Manhattan Study. Patients Randomly selected stroke-free participants from a multiethnic urban community. Main Outcome Measure Incident stroke and other vascular events.

RESULTS

All 5 infectious serological results were available from baseline samples in 1625 participants (mean [SD] age, 68.4 [10.1] years; 64.9% women). Cox proportional hazards models were used to estimate associations of each positive serological test result with stroke. Individual parameter estimates were then combined into a weighted index of infectious burden and used to calculate hazard ratios and confidence intervals for association with risk of stroke and other outcomes, adjusted for risk factors. Each individual infection was positively, though not significantly, associated with stroke risk after adjusting for other risk factors. The infectious burden index was associated with an increased risk of all strokes (adjusted hazard ratio per standard deviation, 1.39; 95% confidence interval, 1.02-1.90) after adjusting for demographics and risk factors. Results were similar after excluding those with coronary disease (adjusted hazard ratio, 1.50; 95% confidence interval, 1.05-2.13) and adjusting for inflammatory biomarkers.

CONCLUSIONS

A quantitative weighted index of infectious burden was associated with risk of first stroke in this cohort. Future studies are needed to confirm these findings and to further define optimal measures of infectious burden as a stroke risk factor.

CKD associates with cognitive decline

Cognitive impairment and chronic kidney disease (CKD) will become increasingly prevalent in the aging US population. Although evidence exists that CKD is a risk factor for cognitive decline, longitudinal studies are limited and largely have excluded ethnically diverse populations. The Northern Manhattan Study includes a population-based, prospective, stroke-free cohort. We assessed global cognitive function annually using the modified Telephone Interview for Cognitive Status (TICS-m) and estimated kidney function using Cockcroft-Gault creatinine clearance (CCl), Modification of Diet in Renal Disease estimated GFR (eGFR), and serum creatinine (sCr). We examined the association between CKD and change in TICS-m scores over time, adjusting for sociodemographic and vascular risk factors. Of 2172 subjects (mean age 71.5 yr, mean follow-up 2.9 yr), 59% were Hispanic, 20% were black, and 63% were women. Participants with a CCl <60 ml/min and those with a CCl between 60 and 90 ml/min performed significantly worse on the TICS-m over time than those with a CCl >90 ml/min, adjusting for potential confounders. Our results were similar when we used eGFR or sCr to estimate kidney function. In conclusion, decreased kidney function associates with greater cognitive decline, even in those with mild CKD. Kidney disease may represent a novel mechanism leading to cognitive impairment and a target for early intervention.

Inflammatory biomarkers of vascular risk as correlates of leukoariosis

BACKGROUND AND PURPOSE

Inflammatory biomarkers, including lipoprotein-associated phospholipase A2 (Lp-PLA2), myeloperoxidase (MPO), and high-sensitivity C-reactive protein (hsCRP) are associated with ischemic stroke risk. White matter hyperintensities (WMH) seen on brain MRI scans are associated with vascular risk factors and an increased risk of incident stroke, but their relation to inflammatory biomarkers is unclear.

METHODS

The Northern Manhattan Study includes a stroke-free community-based sample of Hispanic, black, and white participants with quantitative measurement of WMH volume (WMHV) and inflammatory biomarkers. We measured the association between Lp-PLA2, MPO, and hsCRP levels, and log-transformed WMHV after adjusting for sociodemographic and vascular risk factors.

RESULTS

The hsCRP (median, 2.42 mg/L; IQR, 1.04, 5.19), Lp-PLA2 (median, 220.97 ng/mL; IQR, 185.77, 268.05), and MPO (median, 15.14 ng/mL; IQR, 12.32, 19.69) levels were available in 527 The Northern Manhattan Study participants with WMHV data but no subclinical infarcts. Those with hsCRP in the upper quartile (Q4 >4.92 mg/L or >3 mg/L), Lp-PLA2 in Q4 (>or=264.9 ng/mL), or MPO levels in Q3 (15.04-19.39 ng/mL) or Q4 (>19.39 ng/mL) each had greater WMHV, adjusting for sociodemographic and vascular risk factors. Adjusting for all biomarkers simultaneously, WMHV was 1.3-fold greater for Lp-PLA2 levels in Q4 compared to Q1 (beta=0.28; P=0.008) and 1.25-fold greater for MPO levels above the median compared to below (beta=0.22; P=0.02), but hsCRP was not associated with WMHV.

CONCLUSIONS

Relative elevations of the inflammatory markers Lp-PLA2 and MPO were associated with a greater burden of WMH independent of hsCRP.

Long-term functional recovery after first ischemic stroke: the Northern Manhattan Study

BACKGROUND AND PURPOSE

Several factors predict functional status after stroke, but most studies have included hospitalized patients with limited follow-up. We hypothesized that patients with ischemic stroke experience functional decline over 5 years independent of recurrent stroke and other risk factors.

METHODS

In the population-based Northern Manhattan Study, patients > or =40 years of age with incident ischemic stroke were prospectively followed using the Barthel Index at 6 months and annually to 5 years. Baseline stroke severity was categorized as mild (National Institutes of Health Stroke Scale <6), moderate (6 to 13), and severe (> or =14). Follow-up was censored at death, recurrent stroke, or myocardial infarction. Generalized Estimating Equations provided ORs and 95% CIs for predictors of favorable (Barthel Index > or =95) versus unfavorable (Barthel Index <95) functional status after adjusting for demographic and medical risk factors.

RESULTS

Of 525 patients, mean age was 68.6+/-12.4 years, 45.5% were male, 54.7% Hispanic, 54.7% had Medicaid/no insurance, and 35.1% had moderate stroke. The proportion with Barthel Index > or =95 declined over time (OR, 0.91; 95% CI, 0.84 to 0.99). Changes in Barthel Index by insurance status were confirmed by a significant interaction term (beta for interaction=-0.167, P=0.034); those with Medicaid/no insurance declined (OR, 0.84; P=0.003), whereas those with Medicare/private insurance did not (OR, 0.99; P=0.92).

CONCLUSIONS

The proportion of patients with functional independence after stroke declines annually for up to 5 years, and these effects are greatest for those with Medicaid or no health insurance. This decline is independent of age, stroke severity, and other predictors of functional decline and occurs even among those without recurrent stroke or myocardial infarction.

High-sensitivity C-reactive protein and lipoprotein-associated phospholipase A2 stability before and after stroke and myocardial infarction

BACKGROUND AND PURPOSE

High-sensitivity C-reactive protein (hsCRP) and lipoprotein-associated phospholipase A2 (Lp-PLA2) are hypothesized to be biomarkers of systemic inflammation and risk of myocardial infarction (MI) and stroke. Little is known, however, about the stability of these markers over time, and in particular, about the effects of acute vascular events on these marker levels.

METHODS

Serum samples were collected at 4 annual intervals in 52 stroke-free participants from the Northern Manhattan Study (NOMAS) and assayed for hsCRP and Lp-PLA2 mass and activity levels using standard techniques. Log transformation of levels was performed as needed to stabilize the variance. Stability of marker levels over time was assessed using random effects models unadjusted and adjusted for demographics and other risk factors. In addition, samples from 37 initially stroke-free participants with stroke (n=17) or MI (n=20) were available for measurement before and after the vascular event (median 5 days, range 2 to 40 days). Levels before and after events were compared using nonparametric tests.

RESULTS

HsCRP and Lp-PLA2 activity levels were stable over time, whereas Lp-PLA2 mass levels decreased on average 5% per year (P=0.0015). Using accepted thresholds to define risk categories of Lp-PLA2 mass, there was no significant change over time. HsCRP increased after stroke (from median 2.2 mg/L prestroke to 6.5 mg/L poststroke; P=0.0067) and MI (from median 2.5 mg/L pre-MI to 13.5 mg/L post-MI; P<0.0001). Lp-PLA2 mass and activity levels both decreased significantly after stroke and MI (for Lp-PLA2 mass, from median 210.0 ng/mL to 169.4 ng/mL poststroke, P=0.0348, and from median 233.0 ng/mL to 153.9 post-MI, P<0.0001).

CONCLUSION

Lp-PLA2 mass levels decrease modestly, whereas hsCRP and Lp-PLA2 activity appear stable over time. Acutely after stroke and MI, hsCRP increases whereas Lp-PLA2 mass and activity levels decrease. These changes imply that measurements made soon after stroke and MI are not reflective of prestroke levels and may be less reliable for long-term risk stratification.

Dietary total fat intake and ischemic stroke risk: the Northern Manhattan Study

BACKGROUND

Dietary fat intake is associated with coronary heart disease risk, but the relationship between fat intake and ischemic stroke risk remains unclear. We hypothesized that total dietary fat as part of a Western diet is associated with increased risk of ischemic stroke.

METHODS

As part of the prospective Northern Manhattan Study, 3,183 stroke-free community residents over 40 years of age underwent evaluation of their medical history and had their diet assessed by a food-frequency survey. Cox proportional hazard models calculated risk of incident ischemic stroke.

RESULTS

The mean age of participants was 69 years, 63% were women, 21% were white, 24% black and 52% Hispanic. During a mean of 5.5 years of follow-up, 142 ischemic strokes occurred. After adjusting for potential confounders, risk of ischemic stroke was higher in the upper quintile of total fat intake compared to the lowest quintile (HR 1.6, 95% CI 1.0-2.7). Total fat intake >65 g was associated with increased risk of ischemic stroke (HR 1.6, 95% CI 1.2-2.3). Risk was attenuated after controlling for caloric intake.

CONCLUSIONS

The results suggest that increased daily total fat intake, especially above 65 g, significantly increases risk of ischemic stroke.

Lipoprotein-associated phospholipase A2 activity and risk of recurrent stroke

BACKGROUND

Mass levels of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), a leukocyte-derived enzyme involved in the metabolism of low-density lipoprotein to pro-inflammatory mediators, are associated with prognosis after stroke. Lp-PLA(2) mass correlates only moderately with levels of Lp-PLA(2) activity. The relationship of Lp-PLA(2) activity to risk of stroke recurrence is unknown. We hypothesized that Lp-PLA(2) activity levels would predict risk of recurrence.

METHODS

In the population-based Northern Manhattan Stroke Study, first ischemic stroke patients >or=40 years were followed for recurrent stroke. Levels of Lp-PLA(2) activity were assessed in 467 patients, and categorized by quartile. Cox proportional hazard models were used to calculate hazard ratios (HR) and 95% confidence intervals (95% CI) for risk of recurrent stroke associated with marker quartiles after adjusting for demographics, vascular risk factors, and high-sensitivity C-reactive protein (hsCRP).

RESULTS

Mean age was 68.9 +/- 12.7 years; 54.6% were women; 53.3% Hispanic, 27.2% black, and 17.8% white. Median follow-up was 4.0 years, and there were 80 recurrent strokes. Compared to the lowest quartile of Lp-PLA(2) activity, those in the highest had an increased risk of recurrent stroke (adjusted HR 2.54, 95% CI 1.01-6.39).

CONCLUSION

Stroke patients with Lp-PLA(2) activity levels in the highest quartile, compared to those in the lowest quartile, had an increased risk of recurrence after first ischemic stroke. Further studies are warranted to determine whether this biomarker has clinical utility in determining high-risk populations of stroke survivors, and whether anti-inflammatory strategies that reduce levels of activity of Lp-PLA(2) reduce the risk of stroke recurrence.

Stroke location and association with fatal cardiac outcomes: Northern Manhattan Study (NOMAS)

BACKGROUND AND PURPOSE

Cardiac mortality after stroke is common, and small studies have suggested an association of short-term cardiac mortality with insular location of cerebral infarction. Few population-based studies with long-term follow-up have evaluated the effect of stroke location on the long-term risk of cardiac death or myocardial infarction (MI) after first ischemic stroke. We sought to determine the association between stroke location and cardiac death or MI in a multiethnic community-based cohort.

METHODS

The Northern Manhattan Study is a population-based study designed to determine stroke incidence, risk factors, and prognosis in a multiethnic urban population. First ischemic stroke patients age 40 or older were prospectively followed up for cardiac death defined as fatal MI, fatal congestive heart failure, or sudden death/arrhythmia and for nonfatal MI. Primary brain anatomic site was determined by consensus of research neurologists. Hazard ratios (HRs) and 95% CIs were calculated by Cox proportional-hazards models and adjusted for vascular risk factors (age, sex, history of coronary disease, hypertension, diabetes, cholesterol, and smoking), stroke severity, infarct size, and stroke etiology.

RESULTS

The study population consisted of 655 patients whose mean age was 69.7+/-12.7 years; 44.6% were men and 51.3% were Hispanic. During a median follow-up of 4.0 years, 44 patients (6.7%) had fatal cardiac events. Of these, fatal MI occurred in 38.6%, fatal congestive heart failure in 18.2%, and sudden death in 43.2%. In multivariate models, clinical diagnosis of left parietal lobe infarction was associated with cardiac death (adjusted HR=4.45; 95% CI, 1.83 to 10.83) and cardiac death or MI (adjusted HR=3.30; 95% CI, 1.45 to 7.51). When analysis of anatomic location was restricted to neuroimaging (computed tomography, magnetic resonance imaging, or both [n=447]), left parietal lobe infarction was associated with cardiac death (adjusted HR=3.37; 95% CI, 1.26 to 8.97), and both left (adjusted HR=3.49; 95% CI, 1.38 to 8.80) and right (adjusted HR=3.13; 95% CI, 1.04 to 9.45) parietal lobe infarctions were associated with cardiac death or MI. We did not find an association between frontal, temporal, or insular stroke and fatal cardiac events, although the number of purely insular strokes was small.

CONCLUSIONS

Parietal lobe infarction is an independent predictor of long-term cardiac death or MI in this population. Further studies are needed to confirm whether parietal lobe infarction is an independent predictor of cardiac events and death. Surveillance for cardiac disease and implementation of cardioprotective therapies may reduce cardiac mortality in patients with parietal stroke.

Diabetes, fasting glucose levels, and risk of ischemic stroke and vascular events: findings from the Northern Manhattan Study (NOMAS)

OBJECTIVE

There is insufficient randomized trial data to support evidence-based recommendations for tight control of fasting blood glucose (FBG) among diabetic subjects in primary stroke prevention. We explored the relationship between FBG among diabetic subjects and risk of ischemic stroke in a multiethnic prospective cohort.

RESEARCH DESIGN AND METHODS

Medical and social data and FBG values were collected for 3,298 stroke-free community residents: mean age +/- SD was 69 +/-10 years; 63% were women, 21% were white, 24% were black, and 53% were Hispanic; and follow-up was 6.5 years. Baseline FBG levels were categorized: 1) elevated FBG: history of diabetes and FBG >or=126 mg/dl (7.0 mmol/l); 2) target FBG: history of diabetes and FBG <126 mg/dl (7.0 mmol/l); or 3) no diabetes/reference group. Cox models were used to calculate hazard ratios (HRs) and 95% CI for ischemic stroke and vascular events.

RESULTS

In the Northern Manhattan Study, 572 participants reported a history of diabetes and 59% (n = 338) had elevated FBG. Elevated FBG among diabetic subjects was associated with female sex (P < 0.04), Medicaid (P = 0.01), or no insurance (P = 0.03). We detected 190 ischemic strokes and 585 vascular events. Diabetic subjects with elevated FBG (HR 2.7 [95% CI 2.0-3.8]) were at increased risk of stroke, but those with target FBG levels (1.2 [0.7-2.1]) were not, even after adjustment. A similar relationship existed for vascular events: elevated FBG (2.0 [1.6-2.5]) and target FBG (1.3 [0.9-1.8].

CONCLUSIONS

This prospective cohort study provides evidence for the benefits of tighter glucose control for primary stroke prevention.

Carotid plaque, a subclinical precursor of vascular events: the Northern Manhattan Study

BACKGROUND

Carotid atherosclerosis is a known biomarker associated with future vascular disease. The risk associated with small, nonstenotic carotid plaques is less clear. The objective of this study was to examine the association between maximum carotid plaque thickness and risk of vascular events in an urban multiethnic cohort.

METHODS

As part of the population-based Northern Manhattan Study, carotid plaque was analyzed among 2,189 subjects. Maximum carotid plaque thickness was evaluated at the cutoff level of 1.9 mm, a prespecified value of the 75th percentile of the plaque thickness distribution. The primary outcome measure was combined vascular events (ischemic stroke, myocardial infarction, or vascular death).

RESULTS

Carotid plaque was present in 1,263 (58%) subjects. After a mean follow-up of 6.9 years, vascular events occurred among 319 subjects; 121 had fatal or nonfatal ischemic stroke, 118 had fatal or nonfatal myocardial infarction, and 166 died of vascular causes. Subjects with maximum carotid plaque thickness greater than 1.9 mm had a 2.8-fold increased risk of combined vascular events in comparison to the subjects without carotid plaque (hazard ratio, 2.80; 95% CI, 2.04-3.84). In fully adjusted models, this association was significant only among Hispanics. Approximately 44% of the low-risk individuals by Framingham risk score had a 10-year vascular risk of 18.3% if having carotid plaque.

CONCLUSIONS

Maximum carotid plaque thickness is a simple and noninvasive marker of subclinical atherosclerosis associated with increased risk of vascular outcomes in a multiethnic cohort. Maximum carotid plaque thickness may be a simple and nonexpensive tool to assist with vascular risk stratification in preventive strategies and a surrogate endpoint in clinical trials.

White matter hyperintensities and subclinical infarction: associations with psychomotor speed and cognitive flexibility

BACKGROUND AND PURPOSE

We examined white matter hyperintensity volume (WMHV) and subclinical infarction (no history of clinical stroke; SI) in relation to performance on tests of sequencing, cognitive flexibility, and sensorimotor ability.

METHODS

The Northern Manhattan Study includes a stroke-free community-based sample of Hispanic, Black, and White participants. A subsample (n=656) has undergone measurement of WMHV, SI, and neuropsychological testing. Linear regression was used to examine WMHV and SI in relation to performance on tests of sequencing as measured by Color Trails 1, cognitive flexibility as measured by Color Trails 2, and sensorimotor ability as measured by Grooved Pegboard, using generalized estimating equations (GEE) to account for the correlation among the cognitive tests and other covariates.

RESULTS

Considering performance on the tests of sequencing, cognitive flexibility, and sensorimotor ability simultaneously using GEE, WMHV and subclinical infarction were each associated with worse cognitive performance globally. There was a threshold effect for WMHV with those in the upper quartile performing significantly worse on the tests of cognitive flexibility and sensorimotor ability. Those with frontal SI performed worse on the test of cognitive flexibility and those with deep SI, worse on the test of sequencing.

CONCLUSIONS

Both SI and WMHV were associated with globally worse cognitive performance. Participants with WMH affecting more than 0.75% of cranial volume had significantly slower performance on a task of cognitive flexibility and sensorimotor ability than those in the lowest quartile. The effects of SI on cognitive performance varied by location.

Metabolic syndrome and ischemic stroke risk: Northern Manhattan Study

BACKGROUND AND PURPOSE

More than 47 million individuals in the United States meet the criteria for the metabolic syndrome. The relation between the metabolic syndrome and stroke risk in multiethnic populations has not been well characterized.

METHODS

As part of the Northern Manhattan Study, 3298 stroke-free community residents were prospectively followed up for a mean of 6.4 years. The metabolic syndrome was defined according to guidelines established by the National Cholesterol Education Program Adult Treatment Panel III. Cox proportional-hazards models were used to calculate hazard ratios (HRs) and 95% CIs for ischemic stroke and vascular events (ischemic stroke, myocardial infarction, or vascular death). The etiologic fraction estimates the proportion of events attributable to the metabolic syndrome.

RESULTS

More than 44% of the cohort had the metabolic syndrome (48% of women vs 38% of men, P<0.0001), which was more prevalent among Hispanics (50%) than whites (39%) or blacks (37%). The metabolic syndrome was associated with increased risk of stroke (HR=1.5; 95% CI, 1.1 to 2.2) and vascular events (HR=1.6; 95% CI, 1.3 to 2.0) after adjustment for sociodemographic and risk factors. The effect of the metabolic syndrome on stroke risk was greater among women (HR=2.0; 95% CI, 1.3 to 3.1) than men (HR=1.1; 95% CI, 0.6 to 1.9) and among Hispanics (HR=2.0; 95% CI, 1.2 to 3.4) compared with blacks and whites. The etiologic fraction estimates suggest that elimination of the metabolic syndrome would result in a 19% reduction in overall stroke, a 30% reduction of stroke in women; and a 35% reduction of stroke among Hispanics.

CONCLUSIONS

The metabolic syndrome is an important risk factor for ischemic stroke, with differential effects by sex and race/ethnicity.

Chronic kidney disease is associated with white matter hyperintensity volume: the Northern Manhattan Study (NOMAS)

BACKGROUND AND PURPOSE

White matter hyperintensities have been associated with increased risk of stroke, cognitive decline, and dementia. Chronic kidney disease is a risk factor for vascular disease and has been associated with inflammation and endothelial dysfunction, which have been implicated in the pathogenesis of white matter hyperintensities. Few studies have explored the relationship between chronic kidney disease and white matter hyperintensities.

METHODS

The Northern Manhattan Study is a prospective, community-based cohort of which a subset of stroke-free participants underwent MRIs. MRIs were analyzed quantitatively for white matter hyperintensities volume, which was log-transformed to yield a normal distribution (log-white matter hyperintensity volume). Kidney function was modeled using serum creatinine, the Cockcroft-Gault formula for creatinine clearance, and the Modification of Diet in Renal Disease formula for estimated glomerular filtration rate. Creatinine clearance and estimated glomerular filtration rate were trichotomized to 15 to 60 mL/min, 60 to 90 mL/min, and >90 mL/min (reference). Linear regression was used to measure the association between kidney function and log-white matter hyperintensity volume adjusting for age, gender, race-ethnicity, education, cardiac disease, diabetes, homocysteine, and hypertension.

RESULTS

Baseline data were available on 615 subjects (mean age 70 years, 60% women, 18% whites, 21% blacks, 62% Hispanics). In multivariate analysis, creatinine clearance 15 to 60 mL/min was associated with increased log-white matter hyperintensity volume (beta 0.322; 95% CI, 0.095 to 0.550) as was estimated glomerular filtration rate 15 to 60 mL/min (beta 0.322; 95% CI, 0.080 to 0.564). Serum creatinine, per 1-mg/dL increase, was also positively associated with log-white matter hyperintensity volume (beta 1.479; 95% CI, 1.067 to 2.050).

CONCLUSIONS

The association between moderate-severe chronic kidney disease and white matter hyperintensity volume highlights the growing importance of kidney disease as a possible determinant of cerebrovascular disease and/or as a marker of microangiopathy.

Risk of Myocardial Infarction or Vascular Death After First Ischemic Stroke

BACKGROUND AND PURPOSE

In national guidelines, absolute long-term risk of myocardial infarction (MI) or coronary death determines target low-density lipoprotein levels, but stroke patients are not explicitly addressed. We determined the absolute 5-year risk of cardiovascular outcomes and their predictors after first ischemic stroke in a multiethnic cohort.

METHODS

A population-based cohort of first ischemic stroke patients > or =40 years old was prospectively followed annually for recurrent stroke, MI and cause-specific mortality. Kaplan-Meier 5-year risks for MI or vascular death (primary outcome), and other cardiovascular events, were calculated. Univariate and multivariate Cox proportional hazards models were used to calculate hazard ratios and 95% CI for predictors of cardiovascular outcomes.

RESULTS

Mean age (n=655) was 69.7+/-12.7 years; 55.4% of participants were women, and 51.3% Hispanic. The 5-year risk of MI or vascular death was 17.4% (95% CI, 14.2% to 20.6%). Independent historical predictors of MI or vascular death were age >70 years (hazard ratio 1.62, 1.07 to 2.44), history of coronary artery disease (hazard ratio 1.76, 1.13 to 2.74), and atrial fibrillation (hazard ratio 1.76, 1.05 to 2.94). In the lowest risk group, those < or =70 years old without coronary artery disease, 5-year risk of MI or vascular death was 9.7%.

CONCLUSIONS

The absolute risk of MI or vascular death after ischemic stroke, even in those without high-risk features, approximates levels used by national organizations to designate groups of patients at high risk of vascular events. The comparability of levels of absolute risk among stroke and cardiac patients may have treatment implications.

Gender differences in self-report of recovery after stroke: the Northern Manhattan Study

We compared subjective responses to simple questions after stroke with interviewer-assessed stroke outcome measures. Among those in the highest functional category, women were more likely to report incomplete recovery and greater need for help than men. Among these women, depressed mood was associated with a response of a need for help despite a good functional recovery. Self-reported responses in stroke outcome assessments require further validation by gender and may need to consider the confounding effects of depression.

High-Sensitivity C-Reactive Protein, Lipoprotein-Associated Phospholipase A2, and Outcome After Ischemic Stroke

BACKGROUND

Inflammatory markers have been associated with ischemic stroke risk and prognosis after cardiac events. Their relationship to prognosis after stroke is unsettled.

METHODS

A population-based study of stroke risk factors in 467 patients with first ischemic stroke was undertaken to determine whether levels of high-sensitivity C-reactive protein (hs-CRP) and lipoprotein-associated phospholipase A(2) (Lp-PLA2) predict risk of stroke recurrence, other vascular events, and death.

RESULTS

Levels of Lp-PLA2 and hs-CRP were weakly correlated (r = 0.09; P = .045). High-sensitivity CRP, but not Lp-PLA2, was associated with stroke severity. After adjusting for age, sex, race and ethnicity, history of coronary artery disease, diabetes mellitus, hypertension, hyperlipidemia, atrial fibrillation, smoking, and hs-CRP level, compared with the lowest quartile of Lp-PLA2, those in the highest quartile had an increased risk of recurrent stroke (adjusted hazard ratio, 2.08; 95% confidence interval, 1.04-4.18) and of the combined outcome of recurrent stroke, MI, or vascular death (adjusted hazard ratio, 1.86; 95% confidence interval, 1.01-3.42). After adjusting for confounders, hs-CRP was not associated with risk of recurrent stroke or recurrent stroke, myocardial infarction, or vascular death but was associated with risk of death (adjusted hazard ratio, 2.11; 95% confidence interval, 1.18-3.75).

CONCLUSIONS

Inflammatory markers are associated with prognosis after first ischemic stroke and may offer complementary information. Lipoprotein-associated phospholipase A(2) may be a stronger predictor of recurrent stroke risk. Levels of hs-CRP, an acute-phase reactant, increase with stroke severity and may be associated with mortality to a greater degree than recurrence.