White and black women between the ages of 45 and 64 years may have a lower stroke risk than men of the same age, according to study results published in JAMA Neurology.
A total of 25,789 white (n=15,488) and black (n=10,301) individuals ≥45 years old who had never experienced a stroke were enrolled in the study from 2003 to 2007. Participants were recruited from the Reasons for Geographic and Racial Differences in Stroke cohort. The main outcomes of the analysis included physician-adjudicated incident ischemic stroke, self-reported race/ethnicity, and measured and self-reported risk factors. Follow-up occurred through October 2016, and data were analyzed during 2018.
During a follow-up of 222,120 person-years, 939 ischemic strokes were documented. A higher proportion of strokes occurred in white men (34.7%) compared with black men (16.9%) and white women (25.2%) compared with black women (23.1%). In patients between 45 and 64 years of age, white women had a 32% lower risk for stroke compared with white men (incidence rate ratio [IRR] 0.68 [95% CI, 0.49-0.94]). Similarly, black women had a 28% lower stroke risk vs black men (IRR 0.72; 95% CI, 0.52-0.99).
The lower stroke risk in women was consistent in white individuals until age 74 years (IRR 0.71; 95% CI, 0.55-0.94); however, this was not observed in black individuals (IRR 0.94; 95% CI, 0.68-1.30). Among white participants, variables associated with stroke risk, such as systolic blood pressure (women: hazard ratio [HR] 1.13; 95% CI, 1.05-1.22; men: HR 1.04; 95% CI, 0.97-1.11; P =.099), diabetes (women: HR 1.84; 95% CI, 1.35-2.52; men: HR 1.13; 95% CI, 0.86-1.49; P =.02), and heart disease (women: HR 1.76; 95% CI, 1.30-2.39; men, HR 1.26; 95% CI, 0.99-1.60; P =.09), were more pronounced in women.
A limitation of this study was its observational nature and its lack of generalizability across other races.
The study investigators suggested that although the prevention and management of hypertension, diabetes, and heart disease “is important across all racial/ethnic and sex groups, sex-specific approaches may be warranted in white individuals.”
Howard VJ, Madsen TE, Kleindorfer DO, et al. Sex and race differences in the association of incident ischemic stroke with risk factors [published online December 10, 2018]. JAMA Neurol. doi: 10.1001/jamaneurol.2018.3862