S1669 Obesity as an Independent Risk Factor for Colorectal Dysplasia in Inflammatory Bowel Disease

Introduction: Obesity has been linked to an increased risk of colorectal cancer in the general population, but its relationship with dysplasia among patients with inflammatory bowel disease (IBD) remains uncertain. Given obesity’s pro-inflammatory effects, understanding its role in dysplasia development is increasingly relevant. This study aimed to determine whether obesity is independently associated with colorectal dysplasia among patients with IBD undergoing surveillance colonoscopy. Methods: We performed a retrospective matched case-control study at a tertiary care center among patients who underwent surveillance colonoscopy from 2020 to 2025. Cases were matched 1:1 by age, sex, and IBD subtype. Obesity was defined as mean BMI ≥30 kg/m² within 5 years before colonoscopy. Demographics, clinical characteristics, and histologic findings were collected. Multivariable conditional logistic regression was used to identify independent risk factors for dysplasia. Results: We identified 216 patients with IBD who underwent surveillance colonoscopy (108 with dysplasia, 108 matched non-dysplasia controls). On univariable analysis, obesity was more common among dysplasia cases (30.6%) compared to controls (23.2%), although this difference was not statistically significant (P = 0.22). In a multivariable model adjusting for covariates such as disease duration, prior dysplasia, and histologic severity (inactive/mild/moderate/severe), obesity was independently associated with dysplasia (adjusted odds ratio [aOR] 2.44, 95% CI 1.04-5.71). Additional predictors included longer disease duration (aOR 1.05, 95% CI 1.02-1.08) and prior dysplasia (aOR 5.10, 95% CI 1.50-17.33). Mild histologic inflammation reduced the risk of dysplasia (aOR 0.33, 95% CI 0.14-0.78), and a greater number of prior colonoscopies was modestly protective (aOR 0.88, 95% CI 0.77-0.99). Other variables including family history of colorectal cancer, smoking, diabetes, pseudopolyps, and strictures were not significantly associated with dysplasia. Conclusion: Obesity was independently associated with more than a 2-fold increased odds of colorectal dysplasia in patients with IBD, even after adjusting for clinical and histologic risk factors. These findings support incorporating BMI into dysplasia risk models and suggest that obese patients may benefit from enhanced surveillance strategies.