We investigated the risk of colorectal cancer (CRC) in patients with Crohn’s disease (CD) using the claims data of the Korean National Health Insurance during 2006–2015. The data of 13,739 and 40,495 individuals with and without CD, respectively, were analyzed. Hazard ratios (HRs) were calculated using multivariate Cox proportional hazard regression tests. CRC developed in 25 patients (0.18%) and 42 patients (0.1%) of the CD and non-CD groups, respectively. The HR of CRC in the CD group was 2.07 (95% confidence interval (CI), 1.25–3.41). The HRs of CRC among men and women were 2.02 (95% CI 1.06–3.87) and 2.10 (95% CI, 0.96–4.62), respectively. The HRs of CRC in the age groups 0–19, 20–39, 40–59, and ≥60 years were 0.07, 4.86, 2.32, and 0.66, respectively. The HR of patients with late-onset CD (≥40 years) was significantly higher than that of those with early-onset CD (<40 years). CD patients were highly likely to develop CRC. Early-onset CD patients were significantly associated with an increased risk of CRC than matched individuals without CD. However, among CD patients, late-onset CD was significantly associated with an increased risk of CRC.

Background: Few studies have investigated the risk of gastric cancer (GC) in ulcerative colitis (UC), and the results have been inconsistent. This study aimed to assess the risk of gastric cancer in newly diagnosed UC patients. Methods: Based on claims data from Korean National Health Insurance from January 2006 to December 2015, we identified 30,546 patients with UC and randomly selected 88,829 non-UC individuals as controls, who were matched by age and sex. Multivariate Cox proportional hazards regression was used to calculate adjusted hazard ratios (HRs) for gastric cancer events, with covariates taken into account. Results: During the study period, a total of 77 (0.25%) patients with UC and 383 (0.43%) non-UC individuals were diagnosed with GC. After multivariable adjustment, the HR for GC was 0.60 (95% CI: 0.47–0.77) in patients with UC, using non-UC individuals as the reference group. When stratified by age, the adjusted HRs for GC in UC patients were 0.19 (95% CI: 0.04–0.98) for those aged 20–39 years at the time of UC diagnosis, 0.65 (95% CI: 0.45–0.94) for 40–59, and 0.60 (95% CI: 0.49–0.80) for ≥60 as compared to non-UC individuals in the corresponding age groups. When stratified by sex, the adjusted HR for GC was 0.54 (95% CI: 0.41–0.73) in male UC patients of all ages. Within UC patients, a multivariable analysis revealed that the HR for GC was 12.34 (95% CI: 2.23–68.16) for those aged ≥ 60 years at the time of diagnosis of UC. Conclusions: Patients with UC had a decreased GC risk compared with non-UC individuals in South Korea. Within the UC population, advancing age (≥60 years) was identified as a significant risk factor for GC.

INTRODUCTION: Recent guidelines suggest colorectal cancer (CRC) screening for individuals younger than 50 years of age, but data on the clinical benefits for those aged 40–49 years are scarce. This cohort study using a national database assessed CRC risk in this age group according to colonoscopy status. METHODS: Using diagnostic and procedural codes from the Korean National Health Insurance System claims data from 2004 to 2007, we constructed a 1:2 propensity score-matched colonoscopy cohort (CsC) and noncolonoscopy cohort (NCsC) of patients aged 40–49 years and followed them through 2020. CRC risk was evaluated after propensity score-matched between the CsC and NCsC based on age, sex, income, alcohol consumption, smoking, and the presence of metabolic syndrome. RESULTS: Among 557,638 patients in the CsC and 1,115,276 patients in the NCsC aged 40–49 years at baseline, 4,672 (0.8%) and 14,424 (1.3%) cases of CRC, respectively. The study showed a lower cumulative incidence of CRC in patients who underwent colonoscopies: 0.7% vs 1.0% in their early 40s and 1.0% vs 1.5% in their late 40s. Compared with the NCsC, the adjusted hazard ratio for CRC development in the CsC was 0.62 (95% confidence interval [CI], 0.57–0.67) in men and 0.79 (95% CI, 0.73–0.85) in women in their early 40s and 0.57 (95% CI, 0.54–0.60) in men and 0.74 (95% CI, 0.69–0.78) in women in their late 40s. DISCUSSION: Colonoscopy was associated with a 21%–43% lower CRC risk among individuals in their 40 s, with the greatest risk difference observed in men in their late 40s. These findings highlight the importance of age and sex-specific screening guidelines.