Endogenous sex hormone levels and coronary heart disease risk in postmenopausal women: A meta-analysis of prospective studies

Background: Low testosterone levels have been associated with coronary heart disease (CHD) morbidity and mortality in men, but the influence of hormones in postmenopausal women is unclear. This meta-analysis aimed to examine whether there is an association between endogenous sex hormones and CHD risk in postmenopausal women. Methods: A systematic search of the PubMed and EMBASE databases from 1966 to 30 November 2016 was performed for prospective studies that reported an association between endogenous sex hormones and CHD in postmenopausal women. Summary relative risks (RRs) and 95% confidence intervals (CIs) were combined by using a random-effects model. Results: A total of 13 publications (12 studies, including six prospective cohort and six nested case-control studies) were included. The summary RRs for CHD were 1.01 (95% CI 0.77-1.31) comparing the highest versus lowest tertile of total testosterone, with evidence of high heterogeneity (I-2 = 80.7%). In subgroup and meta-regression analyses, none of the variables were identified as contributing to significant heterogeneity. Based on a comparison of the highest versus lowest tertile models, the summary RRs (95% CIs) for CHD were 0.88 (0.63-1.23, I-2 = 48.7%) for free testosterone, 1.16 (0.82-1.63, I-2 = 47.8%) for estradiol, 0.98 (0.90-1.07, I-2 = 3.2%) for sex hormone-binding globulin and 1.19 (0.89-1.58, I-2 = 0) for dehydroepiandrosterone. Conclusion: There is limited evidence to suggest that endogenous levels of sex hormones are not significantly associated with CHD risk in postmenopausal women.