Obesity and Metabolic Unhealthiness Have Different Effects on Colorectal Neoplasms.

Context: Obesity and insulin resistance are risk factors for colorectal neoplasms (CRN), but data regarding metabolic status, obesity, and CRN are lacking.

Objective: To investigate the relationship between metabolic status, obesity, and CRN in Koreans who underwent colonoscopy.

Design: Retrospective, cross-sectional.

Participants: Subjects were divided based on metabolic and obesity criteria, as follows: metabolically healthy nonobese (MHNO), metabolically healthy obese (MHO), metabolically unhealthy nonobese (MUNO), and metabolically unhealthy obese (MUO).

Main Outcome Measures: Multiple regression was used to identify CRN and advanced CRN risk factors, with the MHNO group as reference.

Results: A total of 10,235 subjects was included, as follows: 5096 MHNO, 1538 MHO, 1746 MUNO, and 1855 MUO. Of these, 3297 had CRN (32.2%), and 434 (4.2%) had advanced CRN. Number of subjects with CRN in each group were: MHNO 25.8%, MHO 33.9%, MUNO 38.9%, and MUO 42.0% (P for trend < 0.001). Risk of CRN was increased in the MHO [odds ratio (OR) 1.239, 95% confidence interval (CI) 1.082 to 1.418, P = 0.002], the MUNO (OR 1.233, 95% CI 1.086 to 1.400, P = 0.001), and the MUO groups (OR 1.510, 95% CI 1.338 to 1.706, P < 0.001), whereas risk of advanced CRN was increased in the MUNO (OR 1.587, 95% CI 1.222 to 2.062, P = 0.001) and the MUO groups (OR 1.456, 95% CI 1.116 to 1.900, P = 0.006).

Conclusions: Obesity increased CRN risk with metabolically unhealthy status adding risk. For advanced CRN, metabolically unhealthy status increased the risk but obesity did not.