Sex differences in the association between major risk factors and the risk of stroke in the UK Biobank cohort study

Objective To determine whether there are sex differences in the association between risk factors and incident stroke, including stroke subtypes. Methods A total of 471,971 (56% women) UK Biobank participants without a history of cardiovascular disease were included. During 9 years of follow-up, 4,662 (44% women) cases of stroke were recorded. Cox models yielded adjusted hazard ratios (HRs) and women-to-men ratios of HRs (RHRs) for stroke associated with 7 risk factors. Results The incidence rate per 10,000 person-years was 8.66 (8.29-9.04) in women and 13.96 (13.44-14.50) inmen for any stroke, 6.06 (5.75-6.38) in women and 11.35 (10.88; 11.84) inmen for ischemic stroke, and 1.56 (1.41-1.73) in women and 2.23 (2.02-2.45) inmen for hemorrhagic stroke. The association between increases in blood pressure, body anthropometry, and lipids, diabetes, and atrial fibrillation and any stroke was similar between men and women. Hypertension, smoking, and a low socioeconomic status were associated with a greater HR of any stroke in women than men; the RHRs were 1.36 (1.26-1.47), 1.18 (1.02-1.36), and 1.17 (1.03-1.33), respectively. Diabetes was associated with a higher HR of ischemic stroke in women than men (RHR 1.25 [1.00-1.56]). Atrial fibrillation was associated with a higher HR of hemorrhagic stroke in women than men (RHR 2.80 [1.07-7.36]). Conclusion Several risk factors are more strongly associated with the risk of any stroke or stroke subtypes in women compared with men. Despite this, the incidence of stroke remains higher among men than women.