RELATION BETWEEN OBESITY AND ADENOMATOUS POLYPS OF THE LARGE BOWEL

Background: We compared the prevalence of colorectal adenoma (polyps) in men and women and examined the role of body mass index (BMI) on polyp risk according to patient age and gender. Methods: The risk of developing colorectal polyps was studied in 15 380 subjects (7155 men and 8225 women) who underwent colonoscopy for the first time from April 1998 to March 2006 at our 'Human Dry Dock', which is the check-up service provided in Japan. Eligible subjects were 20-86 years old (mean age +/- SD, 47.3 +/- 8.5) and were free of invasive cancer, hyperplastic polyps and familial polyposis. Polyps were found in 1590 subjects (1062 men and 528 women). The odds ratio (OR) of detection of polyps in relation to obesity was determined in all cases by multivariate logistic regression analysis after making an adjustment for gender and age. Results: The OR of polyp detection in obese subjects (BMI >= 25) versus non-obese subjects (BMI < 25, OR = 1) was 1.34 (P < 0.001) in men and 1.13 (P = 0.26) in women. As the BMI increased in increments of one, the OR in men increased significantly to 1.01 (P < 0.001), whereas the OR in women was unchanged at 1.00 (P = 0.23), which was without significance. Conclusions: We conclude that obesity in men is a risk factor for the development of polyps. These results must be confirmed by additional epidemiological studies.