Colonoscopy Associated With Lower Colorectal Cancer Risk in Adults Aged 40–49 Years
Colonoscopy was associated with a substantially lower risk of colorectal cancer (CRC) among adults aged 40 to 49 years in a large propensity score–matched cohort study using data from the Korean National Health Insurance System.
Current screening guidelines increasingly recommend consideration of CRC screening before age 50, but evidence supporting screening in younger adults remains limited. To evaluate potential benefits, investigators compared CRC incidence among adults who underwent colonoscopy with those who did not.
The study analyzed claims data collected between 2004 and 2007 and followed participants through 2020. After propensity score matching based on age, sex, income, alcohol consumption, smoking status, and metabolic syndrome, the final cohort included 557,638 individuals who underwent colonoscopy and 1,115,276 individuals who did not.
During follow-up, CRC developed in 4672 participants (0.8%) in the colonoscopy cohort compared with 14,424 participants (1.3%) in the noncolonoscopy cohort.
In adults in their early 40s, CRC incidence was 0.7% in the colonoscopy cohort versus 1.0% in the non-colonoscopy cohort. Among adults in their late 40s, incidence was 1.0% versus 1.5%, respectively.
Risk reductions were observed in both men and women. Compared with individuals who did not undergo colonoscopy, adjusted hazard ratios for CRC development among those who underwent the procedure ranged from 0.57 to 0.79 across age and sex subgroups. The greatest reduction was observed among men in their late 40s, with an adjusted hazard ratio of 0.57 (95% CI, 0.54–0.60).
According to the authors, “colonoscopy was associated with a 21%–43% lower CRC risk among individuals in their 40s.”
Reference
Kim, Su Young, Lee, Seung Won, Kim, Sun Yeup, et al. Association of colonoscopy with colorectal cancer incidence among persons aged 40–49 years: A nationwide population-based claims cohort study. The American Journal of Gastroenterology. 2026
