Potassium Intake and Risk of Stroke in Women With Hypertension and Nonhypertension in the Women’s Health Initiative

Background and Purpose—Dietary potassium has been associated with lower risk of stroke, but there are little data on dietary potassium effects on different stroke subtypes or in older women with hypertension and nonhypertension.

Methods—The study population consisted of 90 137 postmenopausal women aged 50 to 79 at enrollment, free of stroke history at baseline, followed up prospectively for an average of 11 years. Outcome variables were total, ischemic, and hemorrhagic stroke, and all-cause mortality. Incidence was compared across quartiles of dietary potassium intake, and hazard ratios were obtained from Cox proportional hazards models after adjusting for potential confounding variables, and in women with hypertension and nonhypertension separately.

Results—Mean dietary potassium intake was 2611 mg/d. Highest quartile of potassium intake was associated with lower incidence of ischemic and hemorrhagic stroke and total mortality. Multivariate analyses comparing highest to lowest quartile of potassium intake indicated a hazard ratio of 0.90 (95% confidence interval, 0.85–0.95) for all-cause mortality, 0.88 (95% confidence interval, 0.79–0.98) for all stroke, and 0.84 (95% confidence interval, 0.74–0.96) for ischemic stroke. The effect on ischemic stroke was more apparent in women with nonhypertension among whom there was a 27% lower risk with hazard ratio of 0.73 (95% confidence interval, 0.60–0.88), interaction P<0.10. There was no association with hemorrhagic stroke.

Conclusions—High potassium intake is associated with a lower risk of all stroke and ischemic stroke, as well as all-cause mortality in older women, particularly those who are not hypertensive.