Quick Take: Sex and Race Differences in the Association of Incident Ischemic Stroke with Risk Factors

There are large differences in the incidence of stroke among various ethnic groups, as well as between sexes. These differences also vary significantly with age. In this prospective cohort study, 25,789 patients age 45 years and older who were stroke-free from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort (2003-2007) were followed up to October 2016 to investigate incidence and risk factors for ischemic stroke while stratifying by sex for both black and white individuals. Researchers found ischemic stroke incidence rates of 16.9% for black men, 34.7% for white men, 23.1% in black women, and 25.2% in white women. Between the ages of 45 and 64 years, both white women and black women had significantly lower risks of stroke, as compared to white men (incidence rate ratio (IRR) 0.68, 95% CI 0.49 to 0.94) and black men (IRR 0.72, 95% CI 0.52 to 0.99), respectively. Between the ages of 65 and 74 years, white women were still at a lower risk for stroke as compared to white men (IRR 0.71, 95% CI 0.55 to 0.94). However, black women in the same age group had no significant difference in risk as compared to black men (IRR 0.94, 95% CI 0.68 to 1.30). Neither race exhibited significant differences between sexes at ages above 75. No risk factors differed between sexes for black individuals. However, for white individuals, risk factors of systolic blood pressure (women: HR 1.13, 95% CI 1.05 to 1.22; men: HR 1.04, 95% CI 0.97 to 1.11, p=0.099), diabetes (women: HR 1.84, 95% CI 1.35 to 2.52; men: HR 1.13, 95% CI 0.86 to 1.49, p=0.02), and heart disease (women: HR 1.76, 95% CI 1.30 to 2.39; men: HR 1.26, 95% CI 0.99 to 1.60, p=0.09) had a higher association with stroke risk in women, as compared to men. Investigators therefore concluded that women are at lower risk for stroke than men, independent of race, between the ages of 45 and 64 years. However, no difference between the sexes was observed for individuals age 75 years and older. Between ages 65 and 74 years, only white women had significantly lower risk than their same-race male counterparts. Differences between the sexes in terms of risk factors also varied between black and white individuals.

Click to read the study in JAMA Neurology

Image: PD

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