The Frequency and Risk Factors of Colorectal Adenoma in Health Check Up Subjects of South Korea: Relation to Obesity and Metabolic Syndrome

Abstract

Background/Aim: Epidemiologic studies suggested that obesity was associated with the risk for colorectal cancer. However, there is a lack of information about the relationship between obesity or metabolic syndrome and colorectal adenoma. We investigated whether obesity or metabolic syndrome is a risk factor for colorectal adenoma. Method: A total of 1316 subjects who received health check-up including colonoscopy from April 2006 through September 2007 in Chung-Ang University Hospital were included. The frequency and characteristics of colorectal adenomas were analyzed according to various factors such as demographic features, past history, blood test, body mass indexes (BMI), abdominal circumference, metabolic syndrome, and abdominal sonographic finding. The presence of the metabolic syndrome was determined by using the International Diabetes Federation definition. General obesity and abdominal obesity were defined as BMI ≥25 kg/m2 and as waist circumference ≥80 in women and ≥90 cm in men, respectively. Results: The sex ratio of subjects was 1.9:1 (male: female) and the mean age was 47.7 ± 10.0 years. The frequency of colorectal adenomas was 20.0% (263/1316). The frequency of general obesity, abdominal obesity and metabolic syndrome were 30.9%, 32.1 and 21.3%, respectively. In univariate analysis, while the frequency of colorectal adenoma was not different whether subjects belonged to metabolic syndrome or not, abdominal obesity was significantly associated with the frequency of colorectal adenoma (26.5 % yes vs 16.9 % no, p < 0.001). Also, the frequency of colorectal adenoma was significantly higher in male, old age, current smoker, and subjects with fasting hyperglycemia (≥100 mg/dL) or fatty liver (p < 0.05). Multivariate analysis identified that male sex (OR 1.5, 95% CI = 1.0-2.2), old age (age≥60) (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). In the characteristics of colorectal adenomas, the frequency of multiple adenoma (≥2) was also significantly higher in subjects with abdominal obesity (40.2% yes vs 28.5% no, p = 0.047). However, the other characteristics such as proximal adenoma (proximal to splenic flexure) and advanced adenoma (larger than 10 mm, high grade dysplasia, or tubulovillous/villous adenoma) were not associated with abdominal obesity. Conclusions: Abdominal obesity as well as sex and age were the independent risk factors for colorectal adenoma in health check up subjects of South Korea.