Advanced biological aging is linked to a higher risk of adverse health outcomes; however, its association with kidney stone (KS) remains unclear. This cross-sectional study investigated the relationship between biological aging acceleration (BAA) and KS, along with the potential mediating role of insulin resistance, in 18,868 Chinese adults aged 20-80 years undergoing health examinations at Ruijin Hospital between 2020 and 2024. Biological age was assessed using the Klemera-Doubal method biological age (KDM-BA) and Phenotypic age(PhenoAge) algorithms, with BAA calculated via residual analysis relative to the chronological age. Insulin resistance(IR) was evaluated using surrogate indices including the triglyceride glucose index (TyG), TyG-body mass index (TyG-BMI), and metabolic score for insulin resistance (METS-IR). The overall prevalence of KS was 5.25%. After full covariate adjustment, participants in the highest quintile of KDM-BA acceleration had a 1.34-fold higher risk of KS than those in the lowest quintile (95% confidence interval [CI]: 1.05-1.70). Similarly, those in the highest PhenoAge acceleration quintile exhibited a 1.39-fold increase in KS risk (95% CI: 1.10-1.76). KDM-BA and PhenoAge acceleration increased by 12% (odds ratio[OR]: 1.12, 95% CI: 1.04-1.20) and 9% (OR: 1.09, 95% CI: 1.03-1.16) per standard deviation, respectively, in correlation with higher KS risk. Restricted cubic spline analysis confirmed dose-response relationships for both KDM-BA (P-=0.002) and PhenoAge acceleration (P-=0.007) with KS. Mediation analysis indicated that IR accounted for 7-13% of these associations. These results imply that an increased risk of KS is linked to accelerated biological ageing, with IR playing a role in this association in Chinese adults. Metabolic and aging monitoring should be enhanced in patients with KS. overall overall
