Abstract Background and aims Men have a higher incidence of stroke than women. Childhood risk factors are associated with adult cardiovascular disease, but their role in sex differences in stroke remains unclear. We examined whether childhood risk factors contribute to the sex differences in adult stroke incidence. Methods Data were from i3C cohorts in USA, Finland and Australia (1970s-90s). Childhood data included demographics, socioeconomic status (SES, parental education), smoking and age-standardised measures of body mass index (BMI), systolic blood pressure (SBP), total cholesterol, and triglycerides. A subset had adult SES, smoking, BMI, SBP and total cholesterol data. Adult stroke events were identified through linkage, self-report and clinical adjudication. Poisson regression estimated incidence rate ratios (IRR) for females versus males, adjusting for childhood risk factors and, in sensitivity analysis, adult risk factors. Results Among 20,523 participants (54% female, meanSD childhood age 104 years, mean adult age 488 years), 176 experienced a stroke. In 10,252 with complete data, females had a 41% lower incidence of stroke than males (IRR 0.57; 95%CI 0.35-0.94), with a 4% reduction in the sex difference after adjustment for childhood risk factors (adjusted IRR 0.59; 95%CI 0.36-0.98). In sensitivity analyses (n=5,565), adjustment for adult risk factors reduced the sex difference in stroke incidence by 17%; however, childhood BMI and triglycerides remained independently associated with stroke incidence. Conclusions Childhood risk factors predicted adult stroke but explained little of the sex differences; adult risk factors had a greater impact. Life-course prevention strategies are essential to reducing sex differences in stroke incidence. Conflict of interest Tan V. Bui, Hoang T. Phan, Alan R. Sinaiko, David R. Jacobs Jr, Jessica G. Woo, Julia Steinberger, Lydia A. Bazzano, Terence Dwyer, Alison J. Venn, Seana L. Gall: Nothing to disclose
Bui et al. (Fri,) studied this question.