Association between fasting serum glucose levels and incidence of colorectal cancer in Korean men: the Korean Cancer Prevention Study-II

Introduction: The incidence of colorectal cancer (CRC) is steadily increasing worldwide. Numerous studies have demonstrated that diabetes mellitus is related to an increased risk of CRC; however, the association between impaired fasting glucose and CRC is unclear. Therefore, we evaluated the correlation between fasting serum glucose (FSG) levels and the incidence of CRC, which can be used to develop novel methods for preventing CRC.

Methods: A total of 175,677 individuals from the Korean Metabolic Syndrome Research Initiative study were enrolled between 2004 and 2011. The incidence of CRC was assessed during a mean follow-up of 4.7 years. Hazard ratios (HR) for CRC according to FSG levels were calculated with the Cox proportional hazard model adjusted for age, sex, body mass index, smoking status, alcohol consumption, and regular exercise.

Results: The risk of developing CRC in subjects with high FSG was significant (HR, 1.45; 95% confidence interval [CI], 1.10-1.90), and the risk was higher in men (HR, 1.51; 95% CI, 1.12-2.05). The HR of rectal cancer, but not colon cancer, was significantly higher both in the total population and in men in the high FSG group.

Conclusions: The incidence of CRC positively correlated with FSG levels in men. Rectal cancer incidence was especially correlated with high FSG in the site-specific analysis. Therefore, serum glucose levels maybe a potential marker of colorectal cancer. Early detection and intervention for controlling elevated glucose levels may be indicated as a way to prevent carcinogenesis.