Abstract
Background: The association between body mass index (BMI) and the occurrence of colorectal polyp (adenoma) has been reported to differ between men and women. However, no adequate scientific basis for the relationship between obesity and colorectal adenoma among the Japanese has been provided. Therefore, to determine whether obesity is a risk factor for colorectal adenoma, we analyzed the detection rates of colorectal adenoma.
Subjects and Methods: The risk factors for colorectal adenoma were studied in 7, 497 subjects (3, 444 men, 4, 053 women) who were firs-time examinees and were examined by colonoscopy from April 1998 to March 2004 at our‘Human Dry Dock’Eligible examinees were 26-84 years old (mean age±SD: 48.3±8.1) and were free of invasive cancer, hyperplasia and familial polyposis. Adenomatous polyps were found in 717 (482 men, 235 women) subjects. The odds ratio (OR) of detection of colorectal adenoma in relation to obesity was determined for these 717 cases by multivariate analysis consisting of logistic regression after adjusting for gender and age.
Result: The OR for obese subjects (BMI≤25) vs. Non-obese subjects (BMI<25, OR=1) was 1.44 (95% confidence interval [CI] 1.18-1.76, p<0.01) in men and 1.26 (95% CI 0.98-1.69, p=0.13) in women. As the BMI increased by one, the OR in men increased significantly to 1.08 (95% CI 1.04-1.11, p<0.01) but in women the OR increased to 1.03 (95% CI 0.99-1.07, p=0.19), which was without significance.
Conclusions: We conclude that obesity in men is the risk factor for colorectal adenoma. It is very useful for the prevention of colorectal polyp to avoid the obesity, and consequently cancer. To prevent colorectal adenoma and consequently cancer it is important, especially for men, to avoid obesity. The results of this study indicate that colorectal adenoma share a risk factor with other life style related diseases. These results need to be confirmed by additional epidemiological studies.
