Age at Menarche is Linked to Adiposity and Body Fat Distribution: A Nationally Representative Study.

OBJECTIVE: The study comprehensively examined the association between age at menarche and multiple indicators of body adiposity among U.S. women representative of the national population. METHODS: Data from 5,480 women participating in the National Health and Nutrition Examination Survey 2011-2018 were analyzed. Age at menarche was obtained via self-reporting. Qualified technicians measured body mass index and waist circumference. The total and regional body fat were assessed using dual-energy X-ray absorptiometry. RESULTS: The median age at menarche was 13 years. After adjustment for sociodemographic, lifestyle, reproductive and metabolic factors, early menarche (≤11 years) was significantly associated with an elevated risk of general obesity (OR 1.837, 95% CI 1.462-2.308), abdominal obesity (OR 1.576, 95% CI 1.229-2.022), and excess body fat (OR 1.822-95% CI 1.394, 2.381) compared with normal menarche (12-14 years). Furthermore, age at menarche was negatively associated with the android-to-gynoid fat ratio (β = -0.008, 95% CI: -0.012 to -0.004) and positively associated with the leg-to-trunk fat ratio (β = 0.007, 95% CI: 0.001 to 0.013) after multivariate adjustment. DISCUSSION: The study's findings suggest that earlier menarcheal onset is associated with increased adiposity and an unfavorable body fat distribution in adulthood. These results support the importance of reproductive factors in obesity pathophysiology and highlight the need for early preventive interventions among girls experiencing early menarche. CONCLUSION: Earlier menarche is associated with an elevated risk of adiposity and unfavorable body fat distribution among U.S. women. Prospective longitudinal studies are warranted to further assess causality and to explore the mechanisms involved.