Family history of gastric cancer is associated with the risk of colorectal neoplasia in Korean population

Background Family history of cancers at different sites except for colorectum has not been evaluated as a risk factor for colorectal neoplasia (CRN). Aims To investigate CRN risk according to family history of cancers at 12 different sites, including stomach and colorectum. Methods A cross-sectional study was performed on 139,497 asymptomatic Koreans who underwent colonoscopy as part of a health check-up. Results The mean age of the study population was 41.6 and the prevalence of CRN was 16.3%. Multivariate analyses revealed that family histories of CRC (adjusted odds ratio; confidence interval, 1.26; 1.17–1.35) and gastric cancer (1.07; 1.01–1.13) were independent risk factors for CRN. Notably, the risk of CRN increased even more for participants with family histories of both CRC and gastric cancer (1.38; 1.12–1.70). Family history of CRC was associated with risk of CRN in participants aged both <50 and ≥50 years, whereas family history of gastric cancer was associated with risk of CRN in participants aged <50 years (1.22; 1.14–1.30), but not in participants aged ≥50 years (1.08; 0.99–1.18). Conclusions Family history of gastric cancer was an independent risk factor for CRN, especially in those aged <50 years. Persons with family histories of gastric cancer and CRC, especially those with family histories of both, may need to begin colonoscopy earlier.