Association between sleep traits and risk of colorectal cancer: A bidirectional Mendelian randomization study

Abstract

Abstract Background Sleep disorders are closely related to disease, especially the impact on cancer has received increasing attention. This study aimed to investigate whether sleep traits have a causal relationship with colorectal cancer (CRC) through a Two-sample Mendelian randomization study (MR). Methods In this study, we selected genetic instrumental variables (IVs) for seven sleep traits (sleep duration, get up in the morning, chronotype, nap during day, insomnia, snoring, and daytime dozing) from pooled data of published genome-wide association studies (GWAS). Two-sample MR and multivariate MR analysis study were first conducted to assess the causal association between sleep traits and CRC. The reverse MR analysis was evaluated to the causal relationship between CRC and sleep traits. Inverse variance weighting (IVW), MR Egger, and weighted median were applied to perform the primary MR Analysis. Results The multivariate MR analysis found that sleep duration (p = 0.038) and get up in the morning (p = 0.043) were protective effect on CRC, snoring (p = 0.031) were associated with the risk of CRC, get up in the morning (p = 0.003) would reduce the risk of colon cancer, chronotype (p = 0.035) were associated with the risk of colon cancer, and insomnia (p = 0.027) was the protective factor of rectal cancer. There is no evidence found that a causal association between other sleep traits and CRC, colon cancer and rectum cancer through the IVW. Conclusion This study indicated that sleep duration and get up in the morning might keep us away from CRC, especially colon cancer, and snoring is the adverse effect on CRC.