Changes in adiposity and other factors in relation to age at natural menopause: analyses from the coronary artery risk development (CARDIA) study.

OBJECTIVE: The age at natural menopause has subsequent health implications. Earlier age at natural menopause is a risk factor for cardiovascular disease, atherosclerosis, and stroke. Despite extensive study, no clear and conclusive association between anthropometric measures and age at natural menopause has emerged. This study aims to assess whether baseline and/or longitudinal changes in adiposity are associated with age at natural menopause.

METHODS: In all, 2,030 premenopausal women from the Coronary Artery Risk Development in Young Adults study-a prospective study with 25 years follow-up-were included for analysis from 1985 to 1986 until menopause was attained. Anthropometry included body mass index and waist circumference. Discrete-time survival analysis was then used to determine the association between anthropometric measures at baseline, and also their changes with age at natural menopause, while adjusting for various time-varying and invariant covariates in separate models for body mass index and waist circumference.

RESULTS: Multivariate Cox regression analysis showed that baseline body mass index (hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.94-0.98) and baseline waist circumference (HR 0.98, 95% CI 0.97-0.99) significantly increased the risk of later age at natural menopause. Neither time-varying body mass index nor waist circumference indicating change across time associated with age at natural menopause. Premenopausal hypertension was strongly associated with an earlier age at natural menopause.

CONCLUSION: These findings show that age at natural menopause is partly determined by modifiable factors such as premenopausal hypertension and baseline adiposity. These results highlight the importance of both control and prevention of cardiovascular risk factors such as excess weight in early to mid-adulthood before menopause onset.