March 14, 2019Stroke39 citationsOpen Access
Racial Variation in Stroke Risk Among Women by Stroke Risk Factors
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Key Result
Black women had a significantly higher age-adjusted risk of incident stroke compared with white women (HR 1.47; 95% CI 1.33-1.63), with the greatest disparity seen in women aged 50 to <60 years.
Study Design
Type
Cohort (n=126,018)
Structured PICO
Does black race increase the risk of incident stroke in women free of stroke and coronary heart disease at baseline?
P
Population
126,018 women (11,389 black and 114,629 white) from the Women's Health Initiative, free of stroke and coronary heart disease at baseline (1994-1998)
I
Intervention
Black race
C
Comparator
White race
O
Outcome
Incident total, ischemic and hemorrhagic strokeshard clinical
Black women, particularly those aged 50 to <60 years, have a significantly higher risk of stroke compared to white women, highlighting the need for targeted interventions in younger black women.
Main Result
Effect estimate: HR 1.47 (95% CI 1.33-1.63)
Abstract
Background and Purpose— In the United States, black Americans exhibit a greater risk of stroke and burden of stroke risk factors than whites; however, it is unclear whether these stroke risk factors influence stroke risk differently across racial groups. Methods— In total, 126 018 participants of the Women’s Health Initiative (11 389 black and 114 629 white women), free of stroke and coronary heart disease at baseline (1994–1998), were followed through 2010. Participants completed baseline clinical exams with standardized measurements of blood pressure and anthropometrics, medication inventory and self-reported questionnaires on sociodemographics, behaviors/lifestyle, and medical history. Incident total, ischemic and hemorrhagic strokes were updated annually through questionnaires with medical record confirmation. Rate differences (per 100 000 person-years) and hazard ratios (HR) based on multivariable Cox models and were estimated. Results— Over a median of 13 years, 4344 stroke events were observed. Absolute incidence rates were higher in black than white women in each age group. In age-adjusted analyses, the risk of stroke was significantly higher among black compared with white women (HR=1.47, 95% CI, 1.33–1.63); adjustment for stroke risk factors, which may be on the causal pathway, attenuated the estimate. Racial disparities were greatest among women 50 to <60 years (HR=3.48; 95% CI, 2.31–5.26; rate difference =99) and diminished with increasing age (60 to <70 HR=1.80; 95% CI, 1.50–2.16; rate difference =107; ≥70 years: HR=1.26; 95% CI, 1.10–1.43; rate difference =87; P interaction <0.001). Black women 50 to <60 years remained at significantly higher risk than white women after adjustment for stroke risk factors (HR=1.76; 95% CI, 1.09–2.83). Conclusions— There was a moderately greater risk of total stroke among black compared with white women; however, racial disparities were greatest among women aged 50 to <60 years. Interventions targeted at younger black women may provide the greatest benefit in reducing disparities.