Association of age at menarche with hypertension in rural Chinese women

Objective: The study aimed to explore the association of age at menarche with hypertension and whether adiposity and insulin resistance mediated the association in rural Chinese women. Methods: We conducted a cross-sectional study enrolling 7518 women (median age 56 years) from a rural Chinese area from 2013 to 2014. Adiposity was measured by BMI and waist circumference, and insulin resistance was measured by the homeostasis model assessment of insulin resistance (HOMA-IR) index. Odds ratios (ORs) and 95% confidence limits (Cls) for the association of age at menarche with hypertension were estimated by using multivariate logistic regression models. The contribution of adiposity and insulin resistance to the association was estimated by mediation analysis. Results: Among 7518 women, 3187 (42.39%) had hypertension. Age at menarche was inversely associated with hypertension (per additional year of menarche, OR = 0.965, 95% Cl: 0.935-0.995). BMI or waist circumference and HOMA-IR completely mediated the association of age at menarche with hypertension (for BMI and HOMA-IR: total indirect effect: OR = 0.970, 95% Cl: 0.962-0.978 and direct effect: OR = 0.994, 95% Cl: 0.963-1.026; for waist circumference and HOMA-IR: total indirect effect: OR = 0.981, 95% Cl: 0.973-0.988 and direct effect: OR = 0.983, 95% Cl: 0.952-1.014). Conclusion: Early age at menarche was positively associated with hypertension. Adiposity and insulin resistance seemed to be two vital mediators of the association between age at menarche and hypertension in rural Chinese women.