AbstractBACKGROUND AND AIMS
Limited data are available on risk factors for gastric cancer in the United States. We aimed to characterize risk for gastric cancer based on race/ethnicity and 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 sex-matched case-cohort study to evaluate additional risk factors:Helicobacter pyloriinfection, tobacco use, family history, obesity, language, and socioeconomic status. Subgroup analysis was performed for language and socioeconomic status by race/ethnicity.RESULTS
The incidence of gastric cancer in the reference (non-Hispanic white) population was 8.2 (95% confidence interval [CI], 7.7–8.7) cases per 100,000 person-years. Incidence values for Asians, Hispanics, and non-Hispanic black persons were higher: 12.7 (95% CI, 11.1–14.3), 12.7 (95% CI, 11.7–13.7), and 11.8 (95% CI, 10.3–13.2) cases per 100,000 person-years, respectively (allP< .0001). In logistic regression analysis, we found race/ethnicity to be an independent risk factor for gastric cancer; the odds ratio (OR) for non-Hispanic black persons was 1.5 (95% CI, 1.22–1.72;P< .0001), the OR for Hispanics was 1.4 (95% CI, 1.22–1.57;P< .0001), and the OR for Asians was 1.5 (95% CI, 1.28–1.81;P< .0001), compared with the non-Hispanic white population. Other independent risk factors included infection withH pylori(OR, 4.6; 95% CI, 3.8–5.7), smoking history (OR, 1.4; 95% CI, 1.3–1.6), and family history of gastric cancer (OR, 3.4; 95% CI, 2.6–4.4) (allP< .0001). Non-English language was a significant risk factor for gastric cancer in Asians (P= .05). Higher annual median income was associated with reduced risk (OR, 0.84; 95% CI, 0.75–0.95;P= .0004).CONCLUSIONS
In a population study in Southern California, we found racial/ethnic minorities to have a 40%–50% increase in risk of gastric cancer compared with the non-Hispanic white population. In addition toH pyloriinfection, smoking, family history, and low socioeconomic status were also associated with increased risk. Further characterization of high-risk groups may identify populations appropriate for targeted screening.