Racial Differences in Helicobacter pylori CagA Sero-prevalence in a Consortium of Adult Cohorts in the United States.

Abstract

Prevalence of Helicobacter pylori (H. pylori) infection, the main risk factor for gastric cancer, has been decreasing in the United States; 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 U.S. We sought to assess prevalence of CagA-positive H. pylori infection over time by race in the United States. We utilized multiplex serology to quantify antibody responses to H. pylori antigens in 4,476 participants across five cohorts that sampled adults from 1985 to 2009. Using log-binomial regression models, we calculated prevalence ratios and 95% confidence intervals for the association between H. pylori-CagA sero-prevalence and birth year by race. African Americans were three 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 (P trend = 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 (P trend < 0.001) and was independent of educational attainment. Among African Americans, there was no difference by sex; furthermore, sero-prevalence increased with increasing birth year among those with a high school education or less (P = 0.006). Among individuals in the United States born from the 1920s to 1960s, H. pylori-CagA sero-prevalence has declined among Whites, but not among African Americans. Our findings suggest a widening racial disparity in the prevalence of the most virulent form of H. pylori, the main cause of gastric cancer.