Racial Differences in the Association between Parity and Incident Stroke: Results from the REasons for Geographic and Racial Differences in Stroke Study.

BACKGROUND: Circulatory and vascular changes across consecutive pregnancies may increase the risk of later-life cerebrovascular health outcomes. METHODS: The association between parity and incident stroke was assessed among 7674 white and 6280 black women, aged 45 years and older, and enrolled in the REasons for Geographic and Racial Differences in Stroke Study from 2003 to 2007. Parity was assessed at baseline, and incident stroke was ascertained from physician-adjudicated medical records through September 2014. Cox proportional hazards models were used to estimate hazard ratios (HR) for the association between parity and stroke, adjusting for baseline measures. RESULTS: At baseline, 12.7% of white women and 16.2% of black women reported 1 live birth, while 8.2% and 19.0%, respectively, reported 5 or more live births. Mean follow-up time was 7.5 years (standard deviation = 2.8); there were 447 incident strokes. A significant interaction between race and parity was detected (P = .05). Among white women, those with 5 or more live births had a higher stroke risk than those with 1 live birth (HR = 1.57; 95% confidence interval [CI] .93-2.65). However, the association was eliminated after adjustment for baseline characteristics (HR = 1.00, 95% CI .59-1.71). For black women, those with 5 or more live births had the highest stroke risk compared with those with 1 live birth (HR = 1.91, 95% CI 1.25-2.93), but the association was attenuated and no longer statistically significant after adjustment for confounders (HR = 1.40, 95% CI .89-2.18). CONCLUSIONS: In adjusted models, no statistically significantassociations were observed between parity and stroke risk in a diverse cohort of U.S. women. Further studies are needed to elucidate the role of lifestyle and psychosocial factors in the race-specific associations that were observed.

Alcohol Consumption and Incident Stroke Among Older Adults.

Objectives: This study examines the relationship between alcohol consumption and incident stroke among older adults and tests whether alcohol consumption contributes to observed race and sex differences in stroke. Method: Data are from a U.S. national cohort of black and white adults aged 45 and older, the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Current and past drinking levels were reported at baseline (2003-2007). Participants who had never had a stroke were followed for adjudicated stroke events through September 2015 (n = 27,265). We calculated Cox proportional hazard models for stroke, adjusting for demographic, socioeconomic, behavioral, and health characteristics. Results: Participants, mean age 64.7 years, consumed on average 2.2 drinks/week and experienced 1,140 first-time stroke events over median 9.1 years follow-up. Nondrinkers had a 12% higher risk of stroke than current drinkers; the risk of stroke among nondrinkers largely reflected high risks among past drinkers; these differences were explained by socioeconomic characteristics. Among current drinkers, light drinkers had significantly lower stroke risks than moderate drinkers after accounting for demographic, socioeconomic, behavioral, and health characteristics. Implications of alcohol did not differ between blacks and whites but did differ by sex: Especially among women, nondrinkers, and specifically past drinkers, had higher risks; these differences were largely explained by health characteristics and behaviors. Alcohol did not explain race and sex differences in stroke incidence. Discussion: Among older adults, those who used to, but no longer, drink had higher risks of stroke, especially among women; current light drinkers had the lowest risk of stroke.

What is the association of lipid levels and incident stroke?

BACKGROUND: The association between lipid levels and stroke rates is less than lipid levels and coronary heart disease (CHD). OBJECTIVE: To assess if there are geographic, racial, and ethnic differences in total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and triglyceride levels with incident stroke. METHODS: From the REasons for Geographic And Racial Differences in Stroke (REGARDS) study we evaluated baseline levels of LDL-C, HCL-C, TC, Non-HDL-C (Total-HDL-C) and triglycerides in participants free of prevalent stroke at baseline. Cox Proportional-Hazard models were the main analytical tool used to examine the association between incident stroke and lipids. For each adjusted lipid measure (LDL-C, HDL-C, triglycerides, TC, and non-HDL-C) we calculated a series of incremental models. RESULTS: The analysis cohort was 23,867 participants with a mean follow-up time of 7.5±2.9years, and 1031 centrally adjudicated strokes (874 ischemic and 77 hemorrhagic strokes). HDL-C baseline level was associated with an overall unadjusted 13% risk reduction (HR 0.87, 95% confidence interval [CI]: 0.81-0.93; p<0.05; 14% for ischemic and 16% for hemorrhagic strokes), and TC with an 8% (HR 0.92, 95%CI: 0.87-0.99; p<0.05) risk reduction of all strokes. When the results were fully adjusted a significant association was observed only for LDL-C and non-HDL-C and ischemic stroke. There were no significant differences in these associations when adjusted for age, race, age∗race, gender, education, region, or income. CONCLUSION: In a disease free population, LDL-C and non-HDL-C baseline levels are significantly associated with the risk of ischemic stroke.

Is Pulse Pressure an Independent Risk Factor for Incident Stroke, REasons for Geographic And Racial Differences in Stroke.

BACKGROUND: Pulse pressure (PP) is a potential risk factor of stroke. The relationship of incident stroke with systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and PP was examined. METHODS: Data were from the REasons for Geographic And Racial Differences in Stroke national cohort study of 30,239 black and white participants aged ≥45 years, enrolled between 2003 and 2007. PP (SBP-DBP) and MAP (MAP = DBP + 1/3*PP) were calculated. Telephone follow-up occurred every six months for self or proxy-reported suspected stroke events, confirmed using expert adjudication. Cox-proportional hazards models examined the association of incident stroke for the different BP measurements with multivariable adjustment for sociodemographic and clinical risk factors including gender and race. RESULTS: Men and women without prevalent stroke at baseline were analyzed (n = 25,462). During follow-up (mean 6.3±2.3 years, maximum 10 years), 916 strokes occurred. Unadjusted PP (hazard ratio [HR] = 1.30; 95% confidence interval [CI] 1.24-1.35), SBP (HR = 1.22; 95% CI 1.18-1.32), MAP (HR = 1.24; 95% CI 1.16-1.32), and DBP (HR = 1.09; 95% CI 1.01-1.17) were associated with stroke risk; however, after adjustment for SBP and other risk factors, the association with PP was attenuated (HR = 0.98; 95% CI 0.90-1.07), whereas SBP persisted as a predictor (HR = 1.14; 95% CI 1.06-1.23). These associations were consistent across age (younger vs. older >70 years) and race (black vs. white). CONCLUSIONS: PP is positively associated with incident stroke, but not independently from SBP; and, there were no significant gender, racial, or regional differences in that association.

Obtaining Accelerometer Data in a National Cohort of Black and White Adults.

PURPOSE: The objective of this study is to report methodological details and feasibility of conducting an accelerometer ancillary study in a large US cohort being followed for stroke and cognitive decline. METHODS: Reasons for Geographic and Racial Differences in Stroke is a national population-based study of 30,239 blacks and whites, age ≥45 yr, enrolled January 2003 to October 2007. Baseline evaluations were conducted through computer-assisted telephone interview and an in-home visit. Participants are followed by computer-assisted telephone interview every 6 months. Starting with May 2009 follow-up, contingent on accelerometer availability, participants were invited to wear an accelerometer for 7 d. Device inventory was 1150. Accelerometer, instructions, log sheet, and stamped addressed return envelope were mailed to consenting participants. Postcard acknowledgement and reminders and two calls or less were made to encourage compliance. RESULTS: Between May 2009 and January 2013, 20,076 were invited to participate; 12,146 (60.5%) consented. Participation rates by race-sex groups were similar: black women, 58.6%; black men, 59.6%; white women, 62.3%; and white men, 60.5%. The mean age of the 12,146 participants to whom devices were shipped was 63.5 ± 8.7 yr. Return rate was 92%. Of 11,174 returned, 1187 were not worn and 14 had device malfunction, and of 9973 with data, 8096 (81.2%) provided usable data, defined as ≥4 d of 10+ h of wear time, ranging from 74.4% among black women to 85.2% among white men. CONCLUSIONS: Using mail and telephone methods, it is feasible to obtain objective measures of physical activity from a sizeable proportion of a national cohort of adults, with similar participation rates among blacks and whites. Linked with the clinical health information collected through follow-up, these data will allow future analyses on the association between objectively measured sedentary time, physical activity, and health outcomes.