Abstract
Context: Gastric cancer incidence in African Americans is twice that in whites, and differing prevalence of strain-specific Helicobacter pylori infection may explain the disparity.
Objective: To investigate if there are racial differences in Helicobacter pylori infection.
Design, Setting, and Participants: The Southern Community Cohort Study recruited 86,000 participants, two-thirds African American, from 12 southeastern states from 2002-2009. Serum levels of antibodies to Helicobacter pylori proteins were assessed for a sample of 712 African American and non-Hispanic white participants using multiplex serology. Sero-positivity to each Helicobacter pylori protein was defined by predetermined cut-points based on median reporter fluorescence intensity. African and European admixture was estimated using a panel of 276 ancestry genetic markers, with “low,” “medium,” and “high” categories of African ancestry defined as <85%, 85-95%, and ≥95%.
Main Outcome Measures: Odds ratios (ORs) for sero-positivity to antibodies to Helicobacter pyloriproteins, by race and African ancestry.
Results: In this sample of low-income African Americans and whites, 88% of African Americans and 69% of whites were sero-positive for Helicobacter pylori. Being African American, compared to being white, was associated with a 2- to 6-fold increased risk for sero-positivity to 8 of 15 Helicobacter pylori proteins examined, including CagA (OR, 5.88; 95% CI, 4.21 −8.22), and VacA (OR, 2.70; 1.96-3.72), previously established as virulence factors for gastric cancer risk. Compared to whites, African Americans of low, medium, and high African ancestry had 1.5-, 4.1 -, and 5.0-fold increased risks of sero-positivity to Helicobacter pylori, respectively, primarily related to CagA+ strains, for which increasing African ancestry led to 2.7-, 8.7-, and 12.3-fold increased risks, respectively (all Pfor trend <0.0001).
Conclusions: African American race and increasing percentage of genetic estimation of African ancestry are strongly associated with prevalence of infection with Helicobacter pylori, particularly its virulent strains.
Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):B75.