ABSTRACT
BACKGROUND: There is a close connection between type 2 diabetes mellitus and the risk of cancers and related mortality. The principal objective of the present study was to explore the association between type 2 diabetes and colorectal cancer. METHODS: We retrospectively compared 1111 subjects (age > or = 30 years) who were subjected to colonoscopies between June 2006 and June 2009. We evaluated the anthropometric data, presenting symptoms and signs, history of diabetes, laboratory data, colonoscopy findings and biopsy results. We analyzed the correlation between colorectal cancer and influencing factors, and compared the incidence rates of colorectal cancer in the type 2 diabetes and control groups. RESULTS: Four hundreds and seven of the subjects had diabetes mellitus. The incidence of colorectal cancer was increased significantly in type 2 diabetes relative to the control group (7.4% vs. 3.4%, P < 0.05). Colorectal cancer was correlated significantly with age, type 2 diabetes, constipation, anemia, and gastrointestinal symptoms. Following logistic regression analysis, age and constipation were associated significantly with colorectal cancer. In the age below 65 years subgroup, the incidence of colorectal cancer was increased significantly in the type 2 diabetes group relative to the control group. CONCLUSION: Type 2 diabetes was associated with increased colorectal cancer risk. This association was more definite in the subjects younger than 65 years.