Mendelian-based urolithiasis risk concerning fish consumption and fish oil supplement.

The link between fish consumption and urolithiasis risk has been observed in previous observational studies, yet a definitive causal relationship remains uncertain. We acquired data regarding fish consumption, fish oil supplementation, and urolithiasis from publicly available large-scale genome-wide association studies (GWAS). Urolithiasis data were sourced from the FinnGen consortium, comprising 5347 cases and 213,445 controls. Information on fish consumption and fish oil supplementation was extracted from the UK Biobank, encompassing 460,443 samples for oily fish consumption, 460,880 samples for non-oily fish consumption, and 461,384 samples for fish oil intake. We conducted 2-sample Mendelian randomization (MR) analyses employing random effects inverse variance weighting, weighted median, and MR-Egger methods, respectively. Additionally, a sensitivity analysis was executed. Our study revealed a heightened risk of urolithiasis associated with non-oily fish consumption (odds ratio [OR] = 1.78, 95% confidence interval [CI]: 1.04-3.03; P = .03), whereas no causal link was found between oily fish consumption and urolithiasis (OR = 0.92, 95% CI: 0.60-1.40; P = .69). Conversely, fish oil supplementation was linked to a diminished urolithiasis risk (OR: 0.02, 95% CI: 0-0.30; P = .005). Furthermore, our sensitivity analysis yielded no evidence of heterogeneity or pleiotropy in our MR analysis. In summary, our study, utilizing genetic data, suggests that non-oily fish consumption may increase the risk of urolithiasis formation, while fish oil supplementation may mitigate this risk.