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.

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.

Genetic contribution to brachial artery flow-mediated dilation: the Northern Manhattan Family Study.

BACKGROUND: Brachial artery flow-mediated dilation (FMD) is a non-invasive measure of endothelial function. Endothelial dysfunction has been associated with traditional vascular risk factors and increased risk of cardiovascular disease. The importance of genetic contribution to FMD and baseline brachial artery diameter has not been shown in Hispanic populations. The purpose of this study was to estimate the heritability of FMD. METHODS: Flow mediated dilation and brachial artery diameter were measured in a subset of Caribbean Hispanic families from the ongoing Northern Manhattan Family Study (NOMAFS), which studies the contribution of genetics to stroke and cardiovascular risk factors. The age- and sex-adjusted heritability of FMD was estimated using variance component methods. RESULTS: The current data include 620 subjects (97 probands and 523 relatives) from 97 families. The age and sex-adjusted heritability of brachial artery diameter was 0.57 (p<0.01). The age- and sex-adjusted heritability of FMD was 0.20 (p=0.01). After additional adjustment for systolic and diastolic blood pressure, body mass index, smoking, lipid, diabetes mellitus, medication, and baseline brachial artery diameter, the heritability of FMD was 0.17 (p=0.01). CONCLUSIONS: We found modest heritability of FMD. FMD might be a reasonable phenotype for further investigation of genetic contribution to atherosclerosis.