Abstract 101: Early Onset Hypertension Increases Risk of Midlife Stroke Among Black Women

Abstract

Background: Stroke at midlife contributes to earlier mortality and greater disability. There is a critical lack of data about early life stroke risk factors among Black women, a group with higher rates of hypertension compared to other racial groups. The hypothesis of the study is that early onset hypertension increases risk of midlife stroke among Black women. Methods: The Black Women’s Health Study is a prospective study of 59000 Black women from across the US who were followed since 1995. Baseline year for this analysis was the 1999 questionnaire. We included stroke-free participants younger than age 65 (46754 participants, mean age 42±9.6 [range 24-64] years). History of hypertension was determined by self-report, defined as physician-diagnosed hypertension with use of an antihypertensive medication or diuretic, or use of an antihypertensive alone. Ischemic and hemorrhagic stroke were ascertained by self-report at biennial health questionnaires. Using Cox models, we estimated risk of midlife stroke, comparing persons with and without hypertension before age 45, between ages 45-64, and at 10-year age intervals. Follow up was from 1999 until whichever came first: incident stroke, death, loss to follow-up, or end of study follow-up (Dec 31, 2019). Results: At baseline, 2980 (10.5%) of participants age <45 and 7147 (38.7%) of participants between ages 45-64 had hypertension. Stroke occurred in 1485 participants (3.2%) during up to 23 years of follow up (mean 17.1±5.0 years). Compared to women with no history of hypertension, Black women with hypertension before age 45 had a higher risk of midlife stroke (HR=2.23, 95% CI=1.79-2.78), after adjustment for age, neighborhood socioeconomic status, residence in Stroke Belt, smoking, body mass index, and diabetes. Risk was also increased with hypertension at midlife age 45-64 (HR=1.69, 95% CI=1.47-1.95) and was highest among those with hypertension at age 24-34 (HR=3.15, 95% CI=1.92-5.16). Conclusion: Black women with hypertension before age 45 have more than twice the risk of stroke at midlife and hypertension before age 35 more than triples the risk. The findings are important to inform public health interventions to expand hypertension screening and treatment in this high-risk population.