Age at natural and surgical menopause and related factors: NHANES 2013-2023

OBJECTIVES: Premature and early menopause are public health issues that increase the risk for chronic conditions, including cardiovascular disease and osteoporosis. We aimed to estimate the average age at menopause and identify factors associated with age at menopause in a nationally representative sample of American women. METHODS: We used a population-based cross-sectional study to investigate menopause timing in 15,322 women aged 15 years and older from the 2013 to 2023 National Health and Nutrition Examination Survey (NHANES). The outcomes were age at natural and surgical menopause (time-to-events) and menopause onset as multinomial categories (premature, early, typical, late). RESULTS: Life tables demonstrated a median age of natural menopause at 50 years, while survey-adjusted estimates suggested a weighted mean age of 49.5 years (95% confidence interval: 49.2-49.8). The prevalence estimates of premature and early natural menopause in postmenopausal women were 4.6% and 10.0%, respectively. Multivariate Cox proportional hazard models identified less education, smoking, and mild depression as factors associated with younger natural menopause onset, whereas obesity, high blood pressure, high cholesterol, and arthritis were significantly associated with younger age at surgical menopause. In postmenopausal women, less education, little sleep, diabetes, and mild depression demonstrated associations with increased odds for premature natural menopause. CONCLUSIONS: Differences between calculated associations and menopause timing reported in the literature are likely due to methodological and participant inclusion differences. The life table method demonstrates a similar estimate to the commonly reported value for natural menopause onset. Several modifiable factors may provide opportunities for intervention.