Obesity is associated with the risk of colorectal cancer. However, there is a lack of information about the relationship between obesity and colorectal adenoma. We investigated whether general and abdominal obesity are risk factors for colorectal adenoma.
Subjects who received health check-ups, including colonoscopy, from April 2006 to September 2007 in Chung-Ang University Hospital were included (n=1,316). The frequency and characteristics of colorectal adenomas were analyzed according to demographic features, past history, blood tests, body mass index, and components of metabolic syndrome. Abdominal obesity was defined as a waist circumference of ≥80 cm in women and ≥90 cm in men.
The sex ratio of the subjects was 1.9:1 (male:female) and their age was 47.7±10.0 years (mean±SD). In univariate analysis, abdominal obesity was significantly associated with the frequency of colorectal adenoma (26.5% "yes" vs 16.9% "no"; p<0.001). The frequency of colorectal adenoma was significantly higher among males, older patients, current smokers, and subjects with fasting hyperglycemia (≥100 mg/dL) or fatty liver (p<0.05). Multivariate analysis identified that male sex (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.0-2.2), old age (age ≥60 years; OR, 6.7; 95% CI, 3.5-12.5), and abdominal obesity (OR, 1.5; 95% CI, 1.0-2.2) were independent risk factors for colorectal adenoma (p<0.05). The frequency of multiple adenomas (more than two sites) was also significantly higher in subjects with abdominal obesity. However, the effect of abdominal obesity on the development of colorectal adenoma decreased in elderly people.
Abdominal obesity is an independent risk factor for colorectal adenoma and its multiplicity, especially in younger people in South Korea.