The association between the uric acid to high-density lipoprotein cholesterol ratio (UHR) index and obesity in postmenopausal women: a cross-sectional analysis based on the NHANES.

Background: Obesity has emerged as a critical global public health challenge. Postmenopausal women experience significantly elevated risks of metabolic disorders and a marked increase in obesity prevalence due to declining estrogen levels. The uric acid to high-density lipoprotein cholesterol ratio (UHR), an emerging biomarker for metabolic syndrome, is gaining clinical recognition. This study systematically investigates the association between the UHR index and obesity in postmenopausal women and evaluates its predictive value.

Methods: We conducted a cross-sectional analysis of 7,811 postmenopausal women from the 2005-2018 National Health and Nutrition Examination Survey (NHANES). Weighted multivariable logistic regression models, adjusted for sociodemographic characteristics, behavioral patterns, and clinical covariates, were employed to examine the UHR index's association with three obesity indices: body mass index (BMI), waist-to-height ratio (WHtR), and weight-adjusted waist index (WWI). Robustness was assessed through stratified subgroup analyses, interaction tests, restricted cubic spline (RCS) modeling, receiver operating characteristic (ROC) curves, and sensitivity analyses to evaluate nonlinear relationships and predictive performance.

Results: The weighted obesity prevalence was 44.05%. After full adjustment, the highest UHR quartile (Q4) showed significantly elevated obesity risks versus the lowest quartile (Q1): BMI-defined obesity (adjusted OR = 8.08, 95% CI: 6.49-10.09), WHtR-defined obesity (adjusted OR = 29.95, 95% CI: 17.08-52.51), and WWI-defined obesity (adjusted OR = 4.58, 95% CI: 3.70-5.67). Subgroup analyses revealed significant effect modifications by diabetes, cardiovascular disease, and chronic kidney disease status (P for interaction < 0.05 for all three obesity indices). The RCS analysis demonstrated a nonlinear dose-response relationship. ROC analysis indicated superior predictive performance for WHtR-defined abdominal obesity (AUC = 0.795, 95% CI: 0.778-0.813), with sensitivity analyses corroborating the primary findings.

Conclusion: The UHR index exhibits a strong, dose-dependent association with obesity risk in postmenopausal women, persisting after comprehensive covariate adjustment. As a metabolic indicator, the UHR index provides clinically meaningful supplementation to conventional obesity assessments, particularly in capturing metabolically driven obesity risk.