Causal Associations between fish consumption and risk of cancer: a Mendelian randomization study

Background： Previous studies have identified a correlation between the consumption of fish and the risk of cancer. However, the causal relationship between these two factors remains uncertain and necessitates further investigation. Methods： The GWAS data were obtained from the public GWAS database. In two-sample Mendelian Randomization (MR) analysis, various methods including inverse variance weighting (IVW), mr-egger regression, simple mode, weighted median, and weighted model were employed to evaluate the causal association between fish consumption and the risk of cancer. Results： The results of the MR analysis indicated a causal relationship between fish consumption and pancreatic cancer risk (IVW: OR=0.334, 95% CI: 0.137-0.863, P =0.023). However, no significant causal relationship was observed between fish consumption and other types of cancer, including bladder cancer ( P =0.934), colorectal cancer ( P =0.968), gastric cancer ( P =0.788), liver cell carcinoma ( P =0.732), lung cancer ( P =0.596), melanoma skin cancer ( P =0.198), oropharyngeal cancer ( P =0.090), prostate cancer ( P =0.075), and thyroid cancer ( P =0.848). Heterogeneity was identified in the MR analysis between fish consumption and thyroid cancer tool variables ( P =0.039), with no horizontal pleiotropy observed in any tool variables. The sensitivity analysis, employing the leave-one-out method, demonstrated the robustness of the MR analysis results. Conclusion: The MR analysis results revealed a causal relationship between fish consumption and the risk of pancreatic cancer. However, no such causal relationship was observed between fish consumption and other cancers, including bladder cancer, colon cancer, gastric cancer, liver cell carcinoma, lung cancer, melanoma skin cancer, oropharyngeal cancer, prostate cancer, and thyroid cancer.