Body mass index as a predictor of advanced colorectal neoplasia.

Background: Colorectal cancer (CRC) is the third frequent cancer in Korea. There are several risk factors including male sex, older age, smoking and family history of colon cancer. Recently, obesity is thought to be a risk factor for CRC and advanced colon polyps. Therefore, we designed a cross-sectional study to determine the association between BMI and advanced colorectal neoplasia.

Methods: A total of 256 patients with advanced colorectal neoplasia who were diagnosed using colonoscopy between May, 2004 and December, 2011 were included in this study. Advanced colorectal neoplasia was defined large (≥1 cm) adenoma or adenocarcinoma. We compared these patients to a control group consisting of 217 subjects with normal colonoscopic findings recruited during the same period.

Results: Of the 256 patients, there were 132 (51.6%) men, and the mean age was 56.4±12.3 years. The rate of males, alcohol drinker and current smokers was significantly higher in the advanced colorectal neoplasia compared to control group. In the subgroup analysis, the mean age and body mass index (BMI, kg/m(2)) of advanced colorectal neoplasia were higher than control group in the female subjects. However, there were no significant differences between two groups in the male subjects. Multiple logistic regression analysis identified overweight (BMI 23.0-24.9 kg/m(2), odds ratios [OR]=2.022) and obesity (BMI≥25 kg/m(2), OR=2.383) as independent risk factors for advanced colorectal neoplasia.

Conclusions: We suggest that BMI should be considered as an independent risk factor for advanced colorectal neoplasia, and people with high BMI should be recommended to undergo colonocoscopy screening earlier than scheduled.