Association between the triglyceride-glucose index and related indices and kidney cancer risk: a prospective cohort study

Evidence remains limited regarding the association of the triglyceride-glucose (TyG) index and related insulin resistance markers, including the triglyceride-glucose body mass index (TyG-BMI), triglyceride-glucose waist circumference index (TyG-WC), and triglyceride-glucose waist-to-height ratio index (TyG-WHtR), with kidney cancer (KC) risk. Large-scale prospective population-based studies are especially scarce. This study aimed to evaluate the associations of the TyG index and related indices with KC risk. This prospective cohort study used baseline data from the Kailuan Study (2006–2019). After participants with prevalent cancer or missing key data were excluded, 173,342 individuals were included. The TyG index and related indices were calculated and categorised into tertiles. Follow-up continued until 31 December 2022, and incident KC was the primary endpoint. Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Restricted cubic spline (RCS) regression was applied to examine dose–response relationships. During 2,183,817.93 person-years of follow-up (median 14.23 years), 265 incident KC cases were documented. Fully adjusted Cox models demonstrated graded elevated KC risk across ascending tertiles of all four TyG-related indices (all P for trend < 0.01): relative to the lowest tertile (T1), the middle tertiles (T2) of TyG-BMI, TyG-WC and TyG-WHtR were each linked to significantly higher KC risk, whereas the highest tertile (T3) of every index independently associated with increased KC risk. RCS regression revealed positive linear dose–response associations of TyG and TyG-BMI with KC risk. In contrast, positive non-linear relationships were observed for TyG-WC and TyG-WHtR. Elevated levels of the TyG index and related indices were significantly associated with increased KC risk. These findings suggest that monitoring these indices may support risk assessment and provide a basis for future prevention research. The Kailuan Study trial registration number ChiCTRTNCR11001489 https://www.chictr.org.cn/showproj.html?proj=8050 .