Abstract / Summary
Abstract The rising global incidence of early-onset colorectal cancer (CRC) has prompted re-evaluation of screening strategies. This retrospective cross-sectional study aimed to determine the prevalence of colorectal adenoma and CRC and associated clinico-metabolic risk factors among 500 patients younger than 50 years who underwent colonoscopy at Siriraj Hospital between January 2022 and December 2023. The cohort was stratified into three age groups (20–29, 30–39, and 40–49 years), with a secondary analysis comparing the 20–39, 40–44, and 45–49 age subgroups. Multivariable logistic regression analysis was performed to identify independent associated factors for colorectal adenoma and CRC. The prevalence of colorectal adenoma and CRC increased significantly with age: 0% (0/35) in the 20–29 age group, 13.1% (14/107) in the 30–39 age group, and 20.7% (74/358) in the 40–49 age group ( p < 0.001). Secondary analysis revealed a sharp increase in prevalence starting in the early 40s, with 22.7% (30/132) in the 40–44 age group, which was higher than the 9.9% (14/142) observed in the 20–39 age group ( p = 0.004) and similar to the 19.5% (44/226) in the 45–49 age group ( p = 0.463). Multivariable logistic regression model revealed that each 1-year increase in age (aOR 1.06; 95% CI 1.01–1.10; p = 0.018) and male sex (aOR 1.95; 95% CI 1.17–3.25; p = 0.010) were independently associated with a higher prevalence of early-onset colorectal adenoma and CRC. These findings underscore the critical need for prompt diagnostic evaluation and early colonoscopy in adults under 50-particularly males and those in their early 40s-rather than informing average-risk screening guidelines.