Association of the triglyceride-glucose index with prostate cancer risk and prognosis: a systematic review and meta-analysis

The triglyceride-glucose (TyG) index has emerged as a convenient and reliable surrogate marker for insulin resistance (IR) and has been linked to an increased risk of several malignancies. However, its association with prostate cancer (PCa) risk remains uncertain. We therefore conducted a systematic review and meta-analysis to evaluate the association between the TyG index and PCa. We systematically searched Web of Science, PubMed, and Embase from inception to June 1, 2025. Eligible studies were identified according to prespecified inclusion and exclusion criteria. Study quality was assessed by using the Newcastle–Ottawa Scale (NOS). Pooled odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated. To estimate the true effect range in similar studies, the 95% prediction interval (PI) was calculated. Heterogeneity was quantified via Cochran’s Q and I 2 statistic, with meta-regression and subgroup analyses further conducted to identify potential sources of heterogeneity. Of 897 records initially identified, 7 studies (5 case–control and 2 retrospective cohort) involving 581,960 participants met the inclusion criteria. An elevated TyG index was associated with an increased risk of PCa (OR = 4.61, 95% CI: 1.04–20.51, I 2 = 98.2%, P < 0.001, 95% PI: 0.023–916.15) and with higher PCa-related mortality (HR = 1.19, 95% CI: 1.05–1.35, I 2 = 0%, P = 0.699). Subgroup analyses suggested that geographic region and study design were major contributors to heterogeneity. Specifically, in Asian studies OR was 8.06 (95% CI: 2.38–27.38, I 2 = 87.39%), and in the single European study OR was 0.92 (95% CI: 0.84–1.00, I 2 = 0%). While a statistically significant association exists between an elevated TyG index and both increased PCa risk and worse mortality, our findings underscore the substantial heterogeneity and limited evidence in this area, highlighting the need for circumspection. Given the limited number of included studies and the extreme heterogeneity observed, the association should be viewed with considerable reservation. Future research urgently requires more prospective studies, standardized protocols, and harmonized cut‑off values.