Objective: The aim of the study was to determine if early menarche is associated with an increased risk of type 2 diabetes mellitus (T2DM) in rural Chinese women and to estimate the proportion that can be attributed to adiposity.
Methods: A total of 15,346 postmenopausal women were enrolled in this study. Logistic regression and restricted cubic spline analysis were performed to estimate the relationship between age at menarche and T2DM. Mediation analysis was used to investigate whether the association was mediated by body mass index (BMI).
Results: After adjusting for multiple confounders, the early menarche group (≤14 y) had a higher risk of T2DM (odds ratio [OR] = 1.21; 95% CI = 1.06-1.38; P = 0.004) compared with the reference group (16-17 y), whereas the late onset group (≥19 y) had a lower risk of T2DM (OR = 0.78; 95% CI = 0.66-0.92; P = 0.003). BMI partially mediated the association between age at menarche and T2DM, and the proportion of the effect was 28%.
Conclusions: Early menarche increases the risk of T2DM, whereas later menarche decreases the risk. The association seems to be partially mediated by BMI.