Racial and Ethnic Variation in Risk for Gastric Cancer: A Regional US Population Study

Introduction: Limited data is available on risk factors for gastric cancer in the U.S. The objective of our study was to characterize risk for gastric cancer based on race/ethnicity as well as additional established risk factors. Methods: We conducted a retrospective cohort study from 2008 to 2014 from an integrated health care system in Southern California to assess incidence of gastric cancer by race/ethnicity. We then conducted an age- and gender-matched case-cohort study to evaluate additional risk factors: Helicobacter pylori (H. pylori), tobacco use, family history, obesity, language, and socioeconomic status (SES). Sub-group analysis was performed for language and socioeconomic status (SES) by race/ethnicity. Results: Incidence of gastric cancer in the reference non-Hispanic white (NHW) population was 8.2 (7.7,8.7) cases per 100,000 person-year (pyr). Incidence for Asians, Hispanics, and non-Hispanic blacks (NHB) was increased: 12.7 (11.1,14.3), 12.7 (11.7,13.7), 11.8 (10.3,13.2) cases per 100,000 pyr, respectively (all P< 0.0001). Using logistic regression, race/ethnicity was found to be an independent risk factor for gastric cancer: NHB, OR=1.5, 95%CI (1.22,1.72), P< 0.0001, Hispanics OR=1.4, 95%CI (1.22,1.57), P< 0.0001, and Asians OR=1.5, 95%CI (1.28,1.81), P< 0.0001 compared to NHW. H. pylori, OR=4.6 (3.8,5.7), smoking history, OR=1.4 (1.3,1.6), and family history OR=3.4 (2.6,4.4) (all P< 0.0001) were also independent risk factors. Non-English language was significant (P=.05) for Asians. Higher annual median income was associated with reduced risk OR=0.84 (0.75,0.95) P=.0004. Conclusion: Racial/ethnic minorities are at 40-50% increased risk of gastric cancer compared to the NHW population. In addition to H. pylori, smoking, and family history, low SES was also found to be associated with increased risk. Further characterization of high-risk groups may identify populations appropriate for targeted screening.Table 1: Results of Multivariable Analysis, Case-cohortFigure 1