Risk factors associated with colon cancer in adults with obesity and association with prior bariatric surgery:...

Obesity is a known risk factor for colon cancer. The primary objective of this study was to evaluate the association between prior bariatric surgery and colon cancer-related admission, particularly among patients with a coded family history of gastrointestinal malignancy, and to identify major risk factors among adults with obesity.

We analyzed the National Inpatient Sample from 2010 to 2015. The prior bariatric surgery group comprised patients with a history of bariatric surgery, and the control group comprised patients with a body mass index ≥35 without prior bariatric surgery. Colon cancer-related admission was identified using International Classification of Diseases, Ninth Revision (ICD-9) code 153.x. Multivariable logistic regression was performed to compare the odds of colon cancer-related admission between groups.

A total of 2,300,845 patients were included (2,004,804 controls and 296,041 who had prior bariatric surgery). The control group had higher odds of colon cancer-related admission than the prior bariatric surgery group (odds ratio, 1.39; P < .001). Among patients with a coded family history of gastrointestinal malignancy, the control group had higher odds of colon cancer-related admission than the prior bariatric surgery group (odds ratio, 1.73; P < .001). A coded family history of gastrointestinal malignancy and a personal history of colonic polyps were strongly associated with colon cancer-related admission (odds ratio, 7.76 and 2.75, respectively; P < .001 for both).

Prior bariatric surgery was associated with lower odds of colon cancer-related admission in this administrative data set. Because procedure type, body mass index trajectory, postoperative weight loss, and the interval between surgery and cancer diagnosis were unavailable, these findings should be interpreted as associative rather than causal.