Forced Expiratory Volume in the First Second and Aldosterone as Mediators of Smoking Effect on Stroke in African Americans: The Jackson Heart Study.

BACKGROUND: Cigarette smoking is a risk factor for stroke, but the mechanisms by which smoking contributes to stroke are not well understood. This study aimed to evaluate the roles of lung function (represented by forced expiratory volume in the first second (FEV1)) and aldosterone as potential mediators of the association of smoking with stroke. METHODS AND RESULTS: The data were derived from 5010 Jackson Heart Study participants who had mean follow-up of 97.9 months. Using the Cox proportional hazards model, we estimated the hazard ratios of smoking for total stroke with and without adjustment for FEV1 and/or aldosterone at baseline after controlling for the confounders. The hazard ratio for current smoking (versus never smoking) was 2.70 (95% CI 1.71 to 4.25) for total stroke after adjustment for the confounders. Additional adjustment for FEV1 and aldosterone reduced the hazard ratio to 2.32 (95% CI 1.42 to 3.79), suggesting that 22.4% of the excess risk of current smoking for total stroke is mediated by these factors. FEV1 and aldosterone account for 13.1% and 12.1%, respectively, of the excess risk. The hazard ratio for FEV1 increased (0.61 versus 0.65) after including systemic inflammatory marker C-reactive protein, and the hazard ratios for aldosterone were comparable for the models that included all confounders and smoking status with or without different blood pressure measurements. CONCLUSIONS: Our findings suggest that the difference in stroke risk between current and never smokers may develop partially through pathways involving lung function and aldosterone and that the mediation effect through aldosterone is independent of blood pressure.

Leptinemia and its association with stroke and coronary heart disease in the Jackson Heart Study.

BACKGROUND: To examine the association of increased plasma leptin concentration with prevalent stroke and coronary heart disease (CHD) and to examine the genetic contributions of leptin to this association in the Jackson Heart Study cohort. METHODS: A cohort of 5170 participants aged 21-84 years who underwent Exam I during 2000-2004 was analysed. Odds ratios (OR) of prevalent stroke and CHD were calculated using a logistic regression model adjusted for age, smoking, hypertension and waist circumference (WC). Variance component analysis was used to partition the phenotypic variance of leptin into the polygenic and environmental components. RESULTS: The prevalence of stroke and CHD was 4.04% and 5.85% in women, and 4.88% and 8.92% in men, respectively. Body mass index (BMI) and WC were highly correlated with leptin both in men and women. In multivariate analysis stratified by sex, leptin was significantly associated with stroke (OR = 1.97, 95% CI = 1.21-3.21) in women after adjustment for age, smoking, systolic blood pressure, BMI and WC (P = 0.0079). No significant association was observed in men. Heritability of sex-, age-adjusted log-transformed leptin for this cohort was 38.0% and 37.8% after further adjustment for WC and hypertension, respectively. In addition, a sibship effect was also found to be significant and explained 12.2% of the total variance of leptin (P = 0.007). CONCLUSION: There is a significant association of leptin with stroke in women, which is partly influenced by the genetic factor. The findings suggest that leptinemia is an independent risk factor for stroke in African American women.

Cardiovascular risk factors among women in Mississippi in the 1990s.

OBJECTIVES: To identify the prevalence of cardiovascular disease risk factors among Mississippi women from 1991 to 1999, using data from the Behavior Risk Factor Surveillance Survey (BRFSS) and to examine the probability that certain risk factors would occur in certain groups of African American and white women in Mississippi. METHODS: We extracted self-reported data on 9690 women in Mississippi from the BRFSS for 1991 to 1999. We performed logistic regression analyses to examine the independent effects of age and race as relative risks for cardiovascular disease, controlling for socioeconomic status. RESULTS: Odds ratios for cigarette smoking for some African American women, for high blood pressure for some white women, and for diabetes in some white and African American women were significantly elevated. Prevalence data, however, showed that African American women had a higher prevalence of diabetes and overweight than white women did. CONCLUSION: The prevalence of overweight among Mississippi women seemed to increase as they aged. Decreasing obesity should be a major public health priority, as obesity's association with several chronic diseases is well documented and it is very prevalent among Mississippi women. Implementing programs to address unhealthy behaviors is essential for maintaining good health and thus should be strongly encouraged.