Abstract
Previous studies have suggested a potential preventive effect of aspirin on colorectal cancer (CRC), but the causal relationship remains unclear. Based on the summary statistics of genome-wide association studies, Mendelian randomization (MR) method was used to assess the genetically predicted effect of aspirin use on CRC risk. Inverse variance weighted (IVW) was used as the main analysis method. Weighted median, simple mode, weighted mode, and MR-Egger method were used as supplementary analyses to assess causal effects. Sensitivity analyses were performed to verify the reliability of the MR results by MR-Egger intercept test, Cochran's Q test and leave-one-out test. The results of IVW method in MR analysis showed a significant causal relationship between aspirin and CRC risk reduction (odds ratio = 0.062, 95% confidence interval = 0.005-0.836, P = .036). The results obtained by the MR-Egger method, weighted median method, WM method, and SM method were consistent with the IVW method in the direction of effect. Sensitivity results suggested the robustness of our findings. Our study reveals a causal relationship between aspirin and CRC, which provides a new basis for future clinical practice and CRC prevention and treatment research.