Dietary exposures and age at natural menopause: Evidence from the Canadian Longitudinal Study on Aging.

OBJECTIVE: To examine whether ultra-processed food (UPF) intake and adherence to the Prospective Urban Rural Epidemiological (PURE) Healthy Diet Score are associated with age at natural menopause (ANM) among Canadian participants. METHODS: This longitudinal cohort study used data from 1972 biological females aged ≥45 years who were premenopausal at baseline in the Canadian Longitudinal Study on Aging (CLSA). Dietary intake was assessed using the Short Diet Questionnaire (SDQ). UPF intake was estimated using the Nova framework and expressed as times/day, while diet quality was assessed using the PURE Healthy Diet Score (0-28). Cox proportional hazards models estimated associations between dietary exposures and time to natural menopause, adjusting for sociodemographic, lifestyle, and reproductive covariates. RESULTS: Over a mean follow-up of 4.08 ± 1.93 years, 1148 participants experienced natural menopause. In unadjusted analyses, a higher PURE Healthy Diet Score was associated with a shorter time to menopause (hazard ratio [HR] 1.013; 95% confidence interval [CI] 1.001, 1.025), whereas UPF intake was not significantly associated with menopause timing. After adjustment for sociodemographic, lifestyle, and reproductive factors, neither UPF intake (HR 1.024; 95% CI 0.977, 1.073) nor the PURE Healthy Diet Score (HR 1.006; 95% CI 0.986, 1.025) was independently associated with time to natural menopause. Results were consistent in sensitivity analyses. CONCLUSIONS: In this longitudinal cohort, UPF intake and the PURE Healthy Diet Score were not independently associated with menopause timing. These findings suggest that menopause timing may reflect cumulative life-course influences more strongly than dietary exposures measured in midlife.