The combined impact of chronic kidney disease and diabetes on the risk of colorectal cancer depends on sex: A nationwide population-based study

Purpose: Although both chronic kidney disease (CKD) and diabetes mellitus (DM) are considered factors increasing the risk of colorectal cancer (CRC), their impact on CRC is not fully understood. This study was aimed to investigate the impact of CKD, DM, or both diseases on the risk of CRC and to evaluate sex differences therein. Materials and Methods: Using data from the National Health Insurance Service–Health Examination Cohort in Korea, we con-ducted a 1:2 matched case-control study. The disease groups consisted of CKD-/DM+ (n=17700), CKD+/DM-(n=22643), and CKD+/DM+ groups (n=8506). After 1:2 matching by age, sex, and health examination year and month, the healthy control group consisted of 97698 individuals. Results: Multivariate Cox regression analysis showed that the CKD-/DM+, CKD+/DM-, and CKD+/DM+ groups were indepen-dently associated with an increased incidence of CRC, compared with controls [hazard ratio (HR), 1.34, 1.31, and 1.63, respectively; all p<0.001]. Compared to the controls, adjusted HRs for the cumulative incidence of CRC in the CKD-/DM+, CKD+/DM-, and CKD+/DM+ groups were, respectively, 1.32, 1.26, and 1.43 in male and 1.38, 1.39, and 2.00 in female. The HR for CRC incidence was significantly higher for the CKD+/DM+ group than for the CKD-/DM+ or CKD+/DM-group in female; however, this significant difference was not observed in male. Conclusion: In female, having both CKD and DM significantly increases the risk of CRC, compared with having CKD or DM alone. This study suggests a significant difference in the effect of CKD or DM on the risk of CRC according to sex.