Abstract
BACKGROUND: Early onset of menarche is associated with hormonal alterations that may predispose women to diabetes. We investigated the association between age at menarche and incident diabetes in India, a setting with declining menarche age and increasing burden of diabetes. METHODS: Data were from the Cardiometabolic Risk Reduction in South Asia study. Women free of diabetes at baseline (2010-12) were followed until 2021 for incident diabetes, defined as prior medical diagnosis or fasting plasma glucose ≥126 mg/dl or HbA1c ≥6.5%. Age at menarche, in years was collected through self-report. Multivariable Cox proportional hazards regression models, controlling for socio-demographic factors and potentially confounding clinical parameters, estimated the association [hazard ratio (HR)] of menarche age with incident diabetes. Effect modification by obesity status was also assessed. RESULTS: Of 3654 women at risk of diabetes at baseline, mean age was 37.7 [Standard Deviation (SD) = 10.4] years and mean age of menarche was 13.9 (SD = 1.3) years. Younger women (age 20-39 years) had an earlier onset of menarche compared to older women. Over 11 years of follow-up (median: 9.2 years), we observed 390 cases of diabetes [cumulative incidence (CI): 10.7%, 95% CI 9.32-12.33; incidence rate: 12.4 per 1000 person-years (95% CI 11.23-13.69)]. There was no association between age at menarche and incident diabetes, HR = 1.04 (95% CI 0.95-1.14). The null association was consistent in models stratified by obesity status. CONCLUSION: We did not find evidence of an association between age at menarche and incident diabetes in this large cohort of Indian women.