Abstract P473: Early Onset Stroke in the Black Women's Health Study

Abstract

Background: The impact of stroke in young adulthood and mid-life is disproportionately large due to greater disability-adjusted life-years lost and worsened quality of life. There is evidence that stroke incidence has increased among young adults in recent decades, although there is conflicting data, especially among subgroups defined by sex and race. We investigated incidence of early-onset stroke among U.S. Black women. Methods: The Black Women’s Health Study is a prospective study of 59,000 Black women from across the U.S. who have been followed since 1995 (aged 21-69 years, median age of 38 years). Both ischemic and hemorrhagic stroke were ascertained by self-report at biennial health questionnaires through December 31, 2019. Stroke mortality was determined through the National Death Index. We stratified by age group: ages 35-54 and ages 55 and older, to distinguish early onset stroke and stroke occurring in later life. We examined crude incidence rates of total stroke cases (per 1000 person-years) during two sequential 12-year follow up periods, 1995-2007 and 2007-2019. Stroke incidence rates were calculated and modeled with Poisson regression. Results: Incident stroke or stroke death occurred in 2093/58,386 participants (3.58%) during 1,316,545 person-years of follow-up from 1995 to 2019. Among women aged 35-54 years the incidence rate was 1.59 (95% CI 1.46-1.72) in the 1995-2007 period (564 cases/355,601 person-years) and 1.12 (95% CI 1.02-1.23) in the 2007-2019 period (460 cases/409,870 person-years). For participants aged 55 or older the incidence rate was 4.19 (95% CI 3.69-4.73) in the 1995-2007 period (257 cases/61,357 person-years) and 2.83 (95% CI 2.62-3.05) in the 2007-2019 period (678 cases/239,433 person-years). Conclusion: In this preliminary analysis, stroke incidence in Black women decreased across study time periods, from 1995-2019, most clearly among participants aged 55 years or older. These findings are similar to those observed in other population-based cohorts reporting incidence rates among Black Americans, for example in the Atherosclerosis Risk in Communities Study. Black women continue to be a high-risk subgroup for stroke and should be a focus for preventive public health efforts, from as early as young adulthood.