Association between gastric cancer and the family history of gastric cancer: a cross-sectional study using Korean Genome and Epidemiology Study data.

Objective: The risk of gastric cancer based on a family history of gastric cancer remains unclear. The purpose of this study was to investigate the relationship between gastric cancer and family history of gastric cancer within a large cohort in Korea.

Methods: In total 211 708 participants were recruited in the Korean Genome and Epidemiology Study during 2001-2013, and divided into a group with a self-reported personal history of gastric cancer ( n  = 930) and a 1:40 matched control group ( n  = 37 200). We examined the family history of gastric cancer in first-degree relatives for cross-sectional analysis. Logistic regression was used to estimate the odds ratios (ORs) of gastric cancer according to family history, using four models that were adjusted for different confounding variables, including the interaction among a family history of gastric cancer.

Results: After matching the two groups for age and sex, the gastric cancer group had a significantly higher proportion of family history in each relative than the controls ( P  < 0.001). In the adjusted model, the ORs [95% confidence interval (CI)] for gastric cancer with a history of an affected father, mother and sibling were 1.80 (1.38-2.34), 1.95 (1.42-2.69) and 2.98 (2.31-3.83), respectively, compared with those in the control group. There was no statistically significant interaction among a family history of gastric cancer in each relative.

Conclusion: A history of gastric cancer in siblings, among first-degree relatives, is strongly associated with an increased risk of gastric cancer. Regular follow-up and early treatment are recommended for those with a family history of gastric cancer.