Body Roundness Index and Risk of Gestational Diabetes Mellitus in Women of Reproductive Age: NHANES 2007–2018

Gestational diabetes mellitus (GDM) is closely related to obesity. This study investigated whether Body Roundness Index (BRI) is independently associated with GDM and compared its discriminative performance with BMI. We conducted a cross-sectional analysis using data from the 2007-2018 National Health and Nutrition Examination Survey (NHANES). The study included 3,343 women aged 20-44 years who had available data on BRI and GDM. Weighted logistic regression and restricted cubic spline (RCS) models were used to examine the association between BRI and GDM. Subgroup and receiver operating characteristic (ROC) curve analyses were performed to evaluate discriminative performance. Among the 3,343 women, 377 (11.3%) reported GDM. Adjusted weighted multivariate logistic regression showed a 39% increase in GDM risk per BRI unit rise (OR = 1.39; 95% CI: 1.19-1.62; P < 0.0001). Subgroup analysis confirmed consistent correlation. RCS analysis revealed a nonlinear relationship at BRI = 3.55, significant below and above (P < 0.05). Based on ROC curve analysis, BRI (AUC = 0.608) was more effective in discriminating between women with and without GDM compared to BMI (AUC = 0.573). This study demonstrates that elevated BRI is independently associated with GDM risk among US reproductive-aged women and shows superior discriminative performance to BMI. These findings highlight the potential value of BRI as an anthropometric indicator associated with GDM risk.