Impact of body mass index on the risk of colorectal adenoma in a metabolically healthy population.

Metabolically healthy obese (MHO) states exist that seem to be protected from cardiovascular risks. Although obesity is a risk factor for colorectal adenoma (CRA), there has yet to be any study of the risks of CRA in MHO individuals. In this study, we compared CRA prevalence in MHO individuals versus metabolically healthy individuals who were normal in weight. This cross-sectional study involved 18,085 Korean adults (39.1 ± 6.7 years) who had a health checkup including a colonoscopy. High-risk CRA was defined as any adenoma over 1 cm, 3 or more adenomas, adenoma with a villous component, or high-grade dysplasia. Multinomial logistic regression models were used to measure the associations between body mass index (BMI) and the risk of low-risk and high-risk CRA. Low-risk and high-risk CRA were present in 9.3% and 1.4% of the study population, respectively. After adjusting for age, sex, smoking, drinking, exercise, family history of colorectal cancer, education, and use of analgesic and aspirin, compared with normal healthy individuals, the prevalence of low-risk and high-risk CRA was increased in MHO individuals [OR = 1.44; 95% confidence interval (CI), 1.23-1.69 and OR = 1.62; 95% CI, 1.09-2.41, respectively]. In fully adjusted models, the prevalence of low-risk and high-risk CRA was associated with increasing categories of BMI in a dose-response manner (P for trend < 0.001 and 0.01, respectively). Thus, excess body weight, even in the absence of a metabolic unhealthy state, was found to be positively associated with increased presence of CRAs.