Duration of ovarian hormone exposure and atherosclerotic cardiovascular disease in Korean women: the Korean Heart Study.

OBJECTIVE Although reproductive and hormonal factors, such as menarche and menopause, have been reported as independent risk factors for atherosclerotic cardiovascular disease (ASCVD), few studies have examined these factors in East Asian populations. In the Korean Heart Study, ASCVD risk related to duration of ovarian hormone exposure was examined in a cohort of 66,104 Korean women. METHODS Study members were recruited from participants of routine health examinations at health promotion centers across South Korea in 1996-2004. Ovarian hormone exposure was defined as duration between menarche and menopause. Incidence rates for ASCVD, stroke, and ischemic heart disease were examined in relation to ovarian hormone exposure. RESULTS The mean duration of ovarian hormone exposure at study baseline was 33.7 years, and risk for ASCVD was negatively associated with duration. Women with shorter ovarian hormone exposure (<30 y) had a higher risk of developing ASCVD (hazard ratio [HR], 1.30; 95% CI, 1.01-1.68) than women with longer ovarian hormone exposure (35-35 y). In similar comparison groups, women with ovarian hormone exposure shorter than 30 years were at increased risk for developing total stroke (HR, 1.18; 95% CI, 1.00-1.38), thrombotic stroke (HR, 1.30; 95% CI, 1.05-1.61), ischemic heart disease (HR, 1.40; 95% CI, 1.19-1.63), and acute myocardial infarction (HR, 1.73; 95% CI, 1.08-2.47). CONCLUSIONS Our study provides further confirmation of increased cardiovascular risk with shorter reproductive years. Therefore, women with reduced lifetime ovarian hormone exposure should focus on minimizing ASCVD risk by lifestyle modifications such as smoking avoidance or increased physical activities.