Association of age at menarche with type 2 diabetes mellitus among urban Indian women: results from the CARRS study

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.