Early age at menarche associated with increased all-cause mortality

Area of Science:

• Reproductive Epidemiology
• Public Health
• Longevity Research

Background:

• Age at menarche, a key reproductive milestone, may influence long-term health outcomes.
• Understanding the relationship between menarche timing and mortality is crucial for public health strategies.
• Previous studies have suggested potential links, but further investigation in diverse populations is warranted.

Purpose of the Study:

• To investigate the association between age at menarche and all-cause mortality in a large cohort of Japanese women.
• To determine if this association is independent of various lifestyle, anthropometric, and reproductive factors.

Main Methods:

• A population-based prospective cohort study of 55,128 Japanese women aged 40-79 years.
• Follow-up until December 2006, with 6,967 deaths recorded.
• Cox proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI), adjusting for multiple covariates.

Main Results:

• An inverse J-shaped association was observed between age at menarche and all-cause mortality (P for quadratic trend <.01).
• Women with menarche at ≤12 years had a significantly higher risk of all-cause mortality (HR 1.17, 95% CI 1.03-1.33) compared to those aged ≥13 years.
• Women with menarche at ≥18 years also showed a slightly elevated mortality risk (HR 1.05, 95% CI 0.96-1.14).
• These associations remained significant after adjusting for lifestyle, anthropometric, and reproductive factors.

Conclusions:

• Both early (≤12 years) and late (≥18 years) age at menarche are associated with increased all-cause mortality risk in Japanese women.
• The findings suggest that age at menarche may be an independent predictor of mortality.
• Further research is needed to elucidate the underlying biological mechanisms linking menarche timing to longevity.