Association of triglyceride levels and prostate cancer: a Mendelian randomization study

Background The association between triglyceride and prostate cancer (PCa) has been reported in observational studies. However, the causality from triglyceride on PCa remained unknown. Method Two-sample Mendelian randomization (MR) was performed with triglyceride genome-wide association study (GWAS) data from 177,861 individuals and GWAS summary statistics of PCa from 463,010 individuals. Then, 48 single nucleotide polymorphisms (SNPs) of triglyceride were used as instrumental variables (IVs) to conduct MR analysis on PCa. Inverse-variance weighted (IVW), Weighted median, MR-Egger regression, Simple mode and Weighted mode were used for MR analysis. To verify the sensitivity of the data, heterogeneity test, pleiotropy test and leave-one-out sensitivity test were performed. Results Association for an effect of triglyceride on PCa risk was found in IVW (odds ratio [OR]: 1.002, 95% confidence interval (CI): 1.000-1.004, p = 0.016). However, opposing results were observed using the weighted median (OR: 1.001, 95% CI: 0.999-1.003, p = 0.499) and MR-Egger (OR: 0.999, 95% CI: 0.995-1.002, p = 0.401) approach. After MRPRESSO, the same result was obtained by using IVW method (OR: 1.002, 95% CI: 1.001-1.004, p = 0.004). Conclusions The large MR analysis indicated that the potential causal effect of triglyceride on PCa. The odds of PCa would increase with high levels of triglyceride. Keywords: Triglyceride, SNPs, Mendelian randomization, Prostate cancer