Premature Menopause and All-Cause Mortality and Life Span Among Women Older Than 40 Years in the NHANES I Epidemiologic Follow-Up Study: Propensity Score Matching Analysis

Objective: Findings from studies of the long-term effect of premature menopause on risks of all-cause mortality in women are equivocal. We used the approach of propensity score matching to examine the causal association of premature menopause with all-cause mortality and life span among women older than 40 years. Methods: The data were from the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study. We calculated the propensity score of premature menopause using a logistic regression model, then matched premature menopause with nonpremature menopause according to the score and the ratio of 1:1. We estimated mortality hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazard models. We also analyzed and plotted the relationship between age at menopause and reproductive life span with all-cause mortality and life span. Results: The mean age of 1,210 women was 55.4 ± 10.8 years at baseline. The unadjusted and adjusted HRs of all-cause mortality for women with premature menopause were 1.46 (95% CI: 1.08–1.96) and 1.53 (95% CI: 1.13–2.08), respectively, compared to nonpremature menopause. Nonlinear associations were found between age at menopause, reproductive life span, all-cause mortality, and life span. Menopausal age <37.5 years of age or reproductive life span <24 years increased the risk of all-cause mortality. Women with menopausal age <39 years of age or reproductive life span <24 years had a lower mean life span than the overall average of 76 years. Conclusions: Premature menopause significantly increased all-cause mortality risk and shortened life span in women. As women's age at menopause or reproductive life span increases, their overall life span also tends to increase.