Association of Age at Menarche and Modified Metabolic Syndrome Among U.S. Women Aged 20–45: National Health and Nutrition Examination Survey, 2017–2023 ID 3866

INTRODUCTION: Earlier menarche has been linked to adverse cardiometabolic profiles. We assessed whether age at menarche is associated with the prevalence of modified metabolic syndrome among reproductive-age women. METHODS: National Health and Nutrition Examination Survey (NHANES) 2017–2023 data for women aged 20–45 were analyzed. Modified metabolic syndrome was defined as meeting three or more of five components: central obesity, hypertension, dysglycemia, low high-density lipoprotein (HDL) cholesterol, and elevated non-HDL cholesterol. Age at menarche was categorized as 14 years or older (reference), 12–13 years, and 11 years or younger. Survey design variables and appropriate weights were used to yield nationally representative estimates. Age-adjusted prevalence ratios (PRs) and 95% CIs were estimated using survey-weighted Poisson regression with robust standard errors. RESULTS: Among 1,302 women aged 20–45, the weighted prevalence of modified metabolic syndrome was 29.1% overall. Prevalence by menarche category was 34.3% for 11 years or younger, 28.5% for 12–13 years, and 24.1% for 14 years or older. Using 14 years or older as the reference, menarche at 12–13 years was associated with a nonsignificant higher prevalence (PR 1.18; 95% CI, 0.89–1.56; P =.25), while menarche at 11 years or younger was associated with a significantly higher prevalence (PR 1.43; 95% CI, 1.02–2.00; P =.037). CONCLUSIONS/IMPLICATIONS: In U.S. women aged 20–45, earlier menarche is associated with a higher burden of metabolic syndrome compared with menarche at 14 years or older, with a significant increase for 11 years or younger. Capturing menarche timing during preconception and well-woman care may aid cardiometabolic risk stratification and inform targeted prevention efforts.