Early Menarche and Hypertension Among Postmenopausal Women: The Mediating Role of Obesity

Cardiovascular diseases are the leading cause of mortality worldwide and are strongly influenced by obesity and hypertension. Age at menarche has been proposed as an early marker of cardiometabolic risk, but evidence in postmenopausal women is inconsistent, particularly in Mexico. We aimed to evaluate the association between early menarche and obesity and hypertension in postmenopausal women, and to examine whether obesity mediates this relationship.

We conducted a cross-sectional study based on a retrospective review of 462 medical records of postmenopausal women who attended a tertiary hospital in Mexico City between January 2023 and August 2024. Early menarche was defined as <12 years. Obesity and hypertension were identified from records. Associations were estimated using Poisson regression with robust variance to obtain prevalence ratios (PRs) and 95% confidence intervals (CIs). We assessed effect modification by age at menopause and conducted a mediation analysis under the counterfactual framework to estimate the proportion of the menarche-hypertension association explained by obesity.

Early menarche was associated with a higher prevalence of obesity (PR = 1.36, 95% CI = 1.08-1.70) and hypertension (PR = 1.34, 95% CI = 1.06-1.71). Associations were stronger among women with menopause at ≤45 years. Mediation analysis indicated that obesity explained 61.6% of this relationship, with a significant indirect effect (PR = 1.18, 95% CI = 1.05-1.33).

Early menarche was independently associated with obesity and hypertension in postmenopausal women, with obesity acting as a potential intermediary factor. Given the cross-sectional design, causality cannot be established, but the associations observed are biologically and temporally coherent.