Dietary Factors and the Risk of Colorectal Cancer: A Mendelian Randomization Study.

Objective: To examine the causal association between 15 dietary factors and the incidence of colorectal cancer through the application of Mendelian randomization methodology.

Methods: The data associated with 15 dietary factors were derived from the IEU OPEN GWAS database, and the colorectal cancer data were sourced from the FinnGen database. The Inverse Variance Weighting method was the principal research method. Sensitivity analyses were implemented to affirm the robustness of the findings. Additionally, we conducted multivariable Mendelian randomization analyses to adjust for the intake of ω-3 and ω-6 polyunsaturated fatty acids.

Results: In our research, we observed suggestive causal relationships between genetically predicted water intake and the reduced risk of colorectal cancer (OR = 0.54; 95% CI= 0.31 ∼ 0.93; p = 0.028); genetically predicted ω-3 PUFA intake (OR = 1.17; 95% CI= 1.05 ∼ 1.30; p = 0.005) were suggestively associated with the increased risk of colorectal cancer. In the multivariable Mendelian randomization analysis, the effect of ω-3 PUFA intake remains significant after adjusting for the influence of ω-6 PUFA intake. Horizontal pleiotropy was not present in this study.

Conclusions: There exists a suggestive causal association between increased water intake and decreased risk of colorectal cancer, while ω-3 PUFA intake are suggestive linked to the increased risk of colorectal cancer.