Fasting Plasma Glucose and Incident Colorectal Cancer: Analysis of a Nationwide Epidemiological Database

Although diabetes mellitus (DM) was reported to be associated with incident colorectal cancer (CRC), the detailed association between fasting plasma glucose (FPG) and incident CRC has not been fully understood. We assessed whether hyperglycemia is associated with a higher risk for CRC. Analyses were conducted using the JMDC Claims Database [n = 1 441 311; median age (interquartile range), 46 (40-54) years; 56.6% men). None of the participants were taking antidiabetic medication or had a history of CRC, colorectal polyps, or inflammatory bowel disease. Participants were categorized as normal FPG (FPG level < 100 mg/dL; 1 125 647 individuals), normal-high FPG (FPG level = 100-109 mg/dL; 210 365 individuals), impaired fasting glucose (IFG; FPG level = 110-125 mg/dL; 74 836 individuals), and DM (FPG level ≥ 126 mg/dL; 30 463 individuals). Over a mean follow-up of 1137 ± 824 days, 5566 CRC events occurred. After multivariable adjustment, the hazard ratios for CRC events were 1.10 (95% CI 1.03-1.18) for normal-high FPG, 1.24 (95% CI 1.13-1.37) for IFG, and 1.36 (95% CI 1.19-1.55) for DM vs normal FPG. We confirmed this association in sensitivity analyses excluding those with a follow-up of< 365 days and obese participants. The risk of CRC increased with elevated FPG category. FPG measurements would help to identify people at high-risk for future CRC.