Background and purpose: Little research has been conducted into variations in women's health in relation to educational level and social roles in Japan. We sought to examine the effect of educational level on risk of cardiovascular disease and its modification by social roles at work and at home under the Japan Public Health Center-based Prospective Study (JPHC Study) Cohort I.
Methods: We calculated the adjusted hazard ratios of educational level for cardiovascular disease incidence within a 12-year study of 20 543 Japanese women aged 40 to 59 without history of stroke or heart disease.
Results: The respective age and area-adjusted hazard ratios for junior high school education and college or higher education compared to high school education were 1.63 (95% CI: 1.29, 2.06) and 1.41(95% CI: 0.96, 2.05) for total stroke, 2.20 (95% CI: 1.34, 3.60) and 2.20 (95% CI: 1.08, 4.48) for subarachnoid hemorrhage, and 1.90 (95% CI: 1.30, 2.76) and 1.60 (95% CI: 0.87, 2.93) for ischemic stroke. The U-shaped association with risk of total stroke was primarily observed for working women with single social roles at home. No association was found between educational level and risk of coronary heart disease or intraparenchymal hemorrhage.
Conclusions: A potential benefit of multiple social roles was suggested for stroke risk reduction among highly educated working women.