Racial differences in Helicobacter pylori CagA sero-prevalence in a consortium of adult cohorts in the United States.

Background: Prevalence of Helicobacter pylori infection, the main risk factor for gastric cancer, has been decreasing in the US; however, there remains a substantial racial disparity. Moreover, the time-trends for prevalence of CagA-positive H. pylori infection, the most virulent form, are unknown in the US population. We sought to assess prevalence of CagA-positive Helicobacter pylori infection over time by race, in the US. Methods: We utilized multiplex serology to quantify antibody responses to H. pylori antigens in 4,476 participants across 5 cohorts that sampled adults from 1985 to 2009. Using log-binomial regression models, we calculated prevalence ratios (PRs) and 95% confidence intervals (CIs) for the association between H. pylori-CagA sero-prevalence and birth year by race. Results: African Americans were 3-times more likely to be H. pylori-CagA sero-positive than whites. After adjustment, H. pylori-CagA sero-prevalence was lower with increasing birth year among whites (Ptrend=0.001), but remained stable for African Americans. When stratified by sex and education separately, the decline in H. pylori-CagA sero-positivity among whites remained only for females (Ptrend<0.001) and was independent of educational attainment. Among African Americans, there was no difference by sex; further, sero-prevalence increased with increasing birth year among those with a high-school education or less (P=0.006). Conclusions: Among individuals in the US born from the 1920s to 1960s, H. pylori-CagA sero-prevalence has declined among whites, but not among African Americans. Impact: Our findings suggest a widening racial disparity in the prevalence of the most virulent form of Helicobacter pylori, the main cause of gastric cancer.