Age at menarche and cardiovascular disease mortality in Singaporean Chinese women: The Singapore Chinese Health Study

Purpose: To examine whether age at menarche was inversely associated with cardiovascular disease (CVD) mortality in Singaporean Chinese women. Methods: We followed prospectively 34,022 Chinese women aged 45 to 74 at enrollment (1993-1998), with complete data on study variables, through 2009 for primary cause of death from CVD, including coronary heart disease (CHD) and cerebrovascular disease (CERE). Hazard ratios (HRs) for CVD mortality were computed across menarcheal age categories and adjusted for potential confounders and body mass index. Results: Over 460,374 person-years of follow-up, 1852 women died from CVD, 998 from CHD and 557 from CERE. There was a significant interaction between age at menarche and smoking (P < .05). In nonsmokers, age at menarche was inversely associated with risk for CVD and CHD mortality. HRs (and 95% confidence interval) for CVD mortality across menarcheal age categories (≤12, 13-14, 15-16, ≥17) were 1.06 (0.87-1.29), 1 (referent), 0.89 (0.79-1.00), and 0.80 (0.69-0.93), respectively (P_trend < .001); HRs for CHD mortality were 1.06 (0.80-1.34), 1 (referent), 0.76 (0.65-0.90), and 0.72 (0.58-0.88), respectively (P_trend < .001). Among nonsmokers, there was no association between age at menarche and CERE mortality. Among smokers, menarcheal age was not associated with CVD, CHD or CERE mortality. Conclusions: Menarcheal age was inversely associated with risk of CVD mortality in nonsmoking Chinese women.