The Association of Early Menopause with Increased Risk of Acute Myocardial Infarction: The INTERHEART China Study

Background and Aim: Little is known about whether early menopause in Chinese ethnicity is associated with acute myocardial infarction (AMI). We aimed to determine whether self-reported early menopause (either surgical or natural menopause at an age <50 year) was associated with first AMI in Chinese women. Methods: The study population was from the INTERHEART China Study, part of the INTERHEART global study. INTERHEART global study was a standardized case-control study that was designed to evaluate the risk factors for first AMI among 52 countries. Data for demographic factors, education, income, and cardiovascular risk factors were obtained by structured questionnaires. A standard set of questions that inquired about menstrual history was included in the interview. Results: Of the 1,771 Chinese women, 1,563 (88.3%) reported either natural or surgical menopause. In univariate logistic regression model, women with early menopause had higher risk of AMI (odds ratio [OR]: 1.51; 95% confidence interval [CI]: 1.23-1.87). After controlling for age, birth control measures, type of menopause, and other traditional risk factors (including waist/hip ratio, lifestyle factors, history of hypertension and diabetes, psychosocial factors, and apolipoprotein B [ApoB]/A1 [ApoA1]), the risk for AMI remained (OR: 1.36; 95% CI: 1.03-1.79). The population attributable risk for AMI in women with early menopause at <50 years was 10.1% (95% CI: 4.0-20.0) compared with women who had menopause at >= 50 years. Conclusion: Early menopause is associated with increased risk of AMI in Chinese women, independent of other traditional coronary heart disease risk factors.