Metabolic factors are associated with a higher risk of conventional adenoma in males during surveillance colonoscopy: findings from a South Australian cohort

Metabolic factors are associated with an increased risk of colorectal neoplasia, but whether metabolic factors impact individuals already considered at elevated risk of CRC due to a family or personal history of neoplasia is unknown. This study aimed to determine whether metabolic factors are associated with an increased risk of colorectal neoplasia in individuals undergoing surveillance colonoscopy in an Australian cohort. A retrospective cohort study design with a sample size of 2806 was implemented using colonoscopy and metabolic data from a hospital surveillance program. The association between self-reported metabolic factors (obesity, hypertension, type two diabetes (T2DM), dyslipidemia, and a cluster of these factors called metabolic syndrome (MetS)) and diagnosis of colorectal neoplasia, its advanced form, or histopathological subtypes at surveillance colonoscopy was analysed using logistic regression models. Metabolic factors that increased the odds of colorectal neoplasia diagnosis included obesity (adjusted odds ratio (AOR) = 1.61; 95% CI 1.06-2.44), T2DM (AOR = 1.40; 95% CI 1.09-1.80), and MetS (AOR = 1.47; 95%CI 1.10-1.99), with similar findings observed for the association with advanced colorectal neoplasia (obesity: AOR = 1.24; 95% CI 1.01-1.51; T2DM: AOR = 1.29; 95%CI 1.06-1.56; MetS: AOR = 1.45; 95% CI 1.18-1.80). These associations were driven by conventional adenomas (87% of all neoplasia) in males. No associations were observed between metabolic factors and colorectal neoplasia in females, nor for the odds of serrated polyps (p > 0.05). Obesity, T2DM and MetS were significant risk factors for the risk of conventional adenoma in a surveillance population, specifically in males. These metabolic disorders should be considered when determining the frequency of colonoscopy surveillance for males.