P40 Preliminary results of the obesity related colorectal adenoma risk (OSCAR) study

Introduction Obesity and non-alcoholic fatty liver disease (NAFLD) is associated with colorectal neoplasia.1 2 In the UK, colonoscopy is performed for patient symptoms, Bowel Cancer Screening Programme (BCSP), family history or surveillance. We aimed to further explore obesity and NAFLD as risk factors with a view to developing a risk model. Methods OSCAR was a cross sectional study recruiting patients attending for colonoscopy. Patients’ medical history, smoking habits, alcohol intake, medication, family history of CRC, waist circumference/height/weight and bloods results were recorded. Multivariate logistic regression was undertaken to test associations between obesity, NAFLD, other risk factors and colorectal adenomas. Preliminary results are reported. Results 1430 patients were recruited (BCSP 410 [28.6%]; symptomatic 1020 [71.3%]). 698 were male (48.8%) with median age: 59 years. The burden of obesity and liver disease was high (reported in a further abstract). 457 patients (31.9%) had colorectal adenomas, 170 (11.9%) had advanced adenomas, and 59 (4.1%) had CRC. Statin use, smoking, metabolic syndrome, abnormal fatty liver index and ALT level were significantly associated with adenoma in univariate analysis, but not in the multivariable model. Variables in the final multivariate model are displayed below. Neither obesity nor NAFLD (established diagnosis; patient reported or in medical notes) were independently associated with adenoma risk in univariate or multivariate analysis (Obesity: multivariable (mv) OR 1.14 [95%CI 0.9–1.4]; NAFLD: mvOR 0.7 [95%CI 0.3–1.5]). Conclusions Older age, referral route, alcohol excess and hypertension were significantly associated with colorectal adenoma. After accounting for these factors, obesity and NAFLD were not independently associated with adenoma. Further work is exploring adenoma burden and more detailed modelling. References Okabayashi K, et al. Body mass index category as a risk factor for colorectal adenomas: a systematic review and meta-analysis. Am J Gastroenterol. 2012;107(8):1175–85. Ding W, et al. Association between nonalcoholic fatty liver disease and colorectal adenoma: A systematic review and meta-analysis. Int J Clin Exp Med. 2015;8(1):322–333.