Systematic exploration of the causal relationships among gallstones, cholecystectomy, and 33 types of site-specific cancers: A Mendelian randomization study based on after-meta analysis

Background: and aim: The association between gallstones/cholecystectomy and cancer remains inconclusive in the current literature. This study aimed to explore the causal connections between gallstones/cholecystectomy and cancer risk by utilizing a bidirectional two-sample multivariable Mendelian randomization (MVMR) approach with Genome-Wide Association Studies (GWAS) data. Methods Utilizing GWAS data from the UK Biobank and FinnGen, this research employed MVMR analyses to explore the impact of gallstones and cholecystectomy on the risk of 33 distinct cancer types. Instrumental variables for gallstones and cholecystectomy were carefully selected to ensure robust analyses, and sensitivity and heterogeneity tests were conducted to verify the findings' validity. Results MVMR analysis, incorporating data from more than 450,000 individuals for gallstones and cholecystectomy, revealed nuanced associations with cancer risk. Cholecystectomy was associated with a significantly increased risk of nonmelanoma skin cancer (OR = 1.59, 95% CI: 1.21 to 2.10, P = 0.001), while gallstones were linked to a decreased risk of the same cancer type (OR = 0.63, 95% CI: 0.47 to 0.84, P = 0.002). Interestingly, the analysis also suggested that cholecystectomy may lower the risk of small intestine tumors (OR = 0.18, 95% CI: 0.043 to 0.71, P = 0.015), with gallstones showing an inverse relationship, indicating an increased risk (OR = 6.41, 95% CI: 1.48 to 27.80, P = 0.013). Conclusions The multivariable Mendelian randomization analysis highlights the differential impact of gallstones and cholecystectomy on cancer risk, specifically for nonmelanoma skin cancer and small intestine tumors. These results underscore the importance of nuanced clinical management strategies and further research to understand the underlying mechanisms and potential clinical implications of gallstone disease and cholecystectomy on cancer risk.