Association between body roundness index (BRI) and gallstones: results of the 2017-2020 national health and nutrition examination survey (NHANES)

Background Gallstones are associated with obesity, and the BRI is a new obesity index that more accurately reflects body fat and visceral fat levels. The relationship between BRI and gallstone risk is currently unknown, and we aimed to explore the relationship between BRI and gallstone prevalence. Methods A cross-sectional study was conducted utilizing data from the 2017-2020 NHANES involving a total of 5297 participants. To assess the association between BRI and gallstones, we used logistic regression analysis, subgroup analysis, and interaction terms. In addition, we performed restricted cubic spline (RCS) analysis and threshold effects analysis to characterize nonlinear relationships. We assessed the ability of BRI and Body mass index (BMI) to identify gallstones using receiver operating curve (ROC) analysis and area under the curve (AUC), and compared them using the Delong test. Results Of the 5297 participants aged 20 years and older included in the study, 575 had gallstones. In fully adjusted models, a positive association between BRI and gallstone prevalence was observed (OR = 1.16, 95% CI: 1.12-1.20, P < 0.0001). Individuals in the highest quartile of BRI had a 204% increased risk of gallstones compared with those in the lowest quartile (OR = 3.04, 95% CI: 2.19-4.22, P < 0.0001). The correlation between BRI and gallstones persisted in subgroup analyses. RCS analyses showed a nonlinear relationship between BRI and gallstones. The inflection point was further found to be 3.96, and the correlation between BRI and gallstones was found both before and after the inflection point. ROC analysis showed that BRI (AUC = 0.667) was a stronger predictor of gallstones than BMI (AUC = 0.634). Conclusions Elevated BRI is associated with an increased risk of gallstones in the U.S. population, and BRI is a stronger predictor of gallstones than BMI. Maintaining an appropriate BRI is recommended to reduce the incidence of gallstones.