Nonlinear association between triglyceride/high-density lipoprotein cholesterol ratio and kidney stones in Chinese adults: a large cross-sectional study

As the association between metabolic disorders and the incidence of kidney stones has garnered increasing attention, this large-scale cross-sectional study, which included 86,002 Chinese adults, investigated the association between the triglyceride-to-high-density lipoprotein cholesterol (TG/HDL-C) ratio and kidney stones. The study found that the prevalence of kidney stones increased with rising TG/HDL-C ratios ( P < 0.0001). Multivariate logistic regression analysis further confirmed that the TG/HDL-C ratio was positively associated with the risk of kidney stones (OR = 1.09, 95% CI: 1.06–1.12, P < 0.0001). A dose-response analysis based on a restricted cubic spline model revealed a nonlinear positive correlation between the two variables, with an inflection point at a ratio of 1.57; below this threshold, a 1-unit increase in the TG/HDL-C ratio was associated with a 27% increase in the risk of kidney stones (OR = 1.27, 95% CI: 1.17–1.37). Subgroup analyses showed that this positive association was consistent across all subgroups stratified by sex, age, diabetes, hypertension, and obesity, and no significant interactions were observed (P-values for interaction terms were all > 0.05). Statistical decomposition analysis (employing a causal mediation framework) indicated that diabetes accounted for approximately 9.2%–42.6% of the total effect, suggesting a potential mediating pathway; however, due to the inherent limitations of the cross-sectional design, these estimates reflect a statistical decomposition of associations rather than confirmed causal effects. Sensitivity analyses suggest that the proportion of the mediating effect may be a conservative estimate, as the inclusion of fasting blood glucose levels may have led to overcorrection. In summary, the TG/HDL-C ratio, as a simple and cost-effective indicator, aids in identifying individuals at high risk for kidney stones in the context of metabolic syndrome. Future prospective studies are needed to further validate this association and elucidate the temporal relationships among lipid metabolism, glycemic control, and the risk of urolithiasis.