Association between triglyceride–glucose index and gallstone prevalence in American adults: A cross-sectional analysis of NHANES 2017 to 2020 data

To examine the association between the triglyceride–glucose (TyG) index, a surrogate marker of insulin resistance, and gallstone prevalence among U.S. adults. Data from the 2017 to 2020 National Health and Nutrition Examination Survey were utilized. Adults aged ≥ 20 years with complete information on gallstone history, TyG index, and covariates were included (n = 7806). Multivariable logistic regression, subgroup analyses, and smooth curve fitting were employed to assess the TyG–gallstone association. Among 7806 participants, 836 (10.7%) reported gallstones. After full adjustment, each one-unit increase in the TyG index was associated with higher odds of gallstones (odds ratio = 1.51, 95% confidence interval: 1.33–1.71). A nonlinear dose–response relationship was observed, with a significant positive association below a TyG threshold of 8.97 (odds ratio = 2.36, 95% confidence interval: 1.85–3.03). Subgroup analyses demonstrated consistent associations across sex, age, race/ethnicity, diabetes, and hypertension strata (all interaction P > .05). A higher TyG index is independently associated with increased gallstone prevalence in U.S. adults. These findings support a potential role of insulin resistance in gallstone pathogenesis and warrant longitudinal studies to establish causality.