General obesity, central obesity, and high triglycerides increase risk of precancerous polyps in colorectal cancer surveillance

INTRODUCTION: While the association between metabolic factors and risk of colorectal cancer (CRC) in the general population is well established, their effect on precancerous polyps among individuals undergoing surveillance colonoscopy is not well understood. Additionally, most guidelines do not consider metabolic factors when determining surveillance colonoscopy intervals. This systematic review and meta-analysis summarizes current evidence for this association in individuals at above-average risk for CRC. METHODS: Relevant studies published from 2010 through 2023 were identified using seven databases. Two independent reviewers performed abstract and full-text screening and quality assessment. Effect estimates were reported using a pooled odds ratio (POR) or pooled hazard ratio (PHR) based on the primary studies measurement with 95% confidence intervals and heterogeneity was reported as I. RESULTS: 15,486 studies were screened, with 24 meeting the inclusion criteria. General obesity (POR = 1.31, 95% CI 1.09-1.57, I = 67%), central obesity (POR = 1.31, 95% CI 1.16-1.49, I = 0%), hypertension (POR = 1.22, 95% CI 1.02-1.44, I = 57%), high triglyceride (POR = 1.39, 95% CI 1.06-1.83, I = 0%), and metabolic syndrome (PHR = 1.24, 95% CI 1.01-1.51, I = 24%) were significant risk factors for the development of any precancerous polyp. The association between diabetes and nonalcoholic fatty liver disease and overall precancerous polyps was inconsistent. General obesity (PHR = 3.04, 95% CI 2.01-4.60, I = 0%) but not diabetes (PHR = 1.07, 95% CI 0.72-1.57, I = 0%) was significantly associated with the risk of advanced precancerous polyps. CONCLUSION: Metabolic factors should be considered when recommending surveillance colonoscopy intervals, which in most guidelines are mainly determined based on the findings at colonoscopy, the significance of family history of CRC and genetic predispositions.