Menarche characteristics in association with total and cause-specific mortality: a prospective cohort study of Mexican teachers.

PURPOSE:We evaluated the relation between age at menarche and time to menstrual regularity with all-cause and cause specific mortality in a cohort of Mexican women. METHODS:We followed 113,540 women from the Mexican Teachers' Cohort. After a mean follow-up time of 9.2 years, 1,355 deaths were identified. We estimated hazard ratios from Cox regression models for total mortality and a competitive risk models for cause-specific mortality adjusting for year of birth and childhood factors. RESULTS:Women with extreme age of menarche were at increased risk of all-cause mortality (HR [95% CI]: <11 years 1.50 [1.20, 1.87]; 14 years 1.19 [0.97, 1.43]) relative to those with menarche at 13 years. Extreme ages at menarche had higher risk of mortality for diabetes (HR: <11 years 1.66 [0.90, 3.05]; 14 years 1.47 [0.90, 2.40]), breast cancer (HR: <11 years 1.34 [0.56, 3.20]), and other cancer (HR:<11 years 1.65 [1.10, 2.48]) compared to menarche at 13 years. Women who took three or more years to achieve menstrual regularity had a higher risk of all-cause mortality compared to those who took less (HR: 1.27 [1.01, 1.58]). CONCLUSIONS:Extreme ages at menarche and longer time to reach menstrual regularity were associated with an increased rate of all-cause and cause-specific mortality.