Earlier age at menarche is associated with higher diabetes risk and cardiometabolic disease risk factors in Brazilian adults: Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Objectives: Early menarche has been linked to higher risk of type 2 diabetes in Western and Asian societies, yet whether age at menarche is associated with diabetes in Latin America, where puberty and diabetes may have different life courses, is unknown. We tested the hypothesis that earlier menarche is associated with higher diabetes risk in Brazilian adults.

Methods: We used data from 8,075 women aged 35-74 years in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) who had complete information on age at menarche, diabetes status, and covariates. Diabetes was defined based on self-reported physician diagnosis, medication use, and laboratory variables (fasting glucose, 2-hour glucose, and glycated hemoglobin). Poisson regression was used to generate risk ratios (RR) and 95% confidence intervals (CI).

Results: Menarche onset < 11 years [vs. 13-14 years (referent)] was associated with higher risk of diabetes (RR = 1.34; 95% CI: 1.14-1.57) after adjusting for sociodemographic factors, maternal education, maternal and paternal diabetes, and birth weight. This persisted after further control for BMI at age 20 years and relative leg length. Additionally, among those not taking diabetes medications, earlier menarche [<11 years vs. 13-14 years (referent)] was associated with higher % glycated hemoglobin (p < 0.001), alanine aminotransferase (p < 0.001), triglycerides (p < 0.001), C-reactive protein (p = 0.003), waist circumference (p < 0.001), and BMI measured at baseline exam (p < 0.001).

Conclusion: These findings support the hypothesis that earlier menarche is associated with greater risk for adult diabetes and cardiometabolic disease in the Brazilian context.