Assessing Helicobacter Pylori Infections Among Adults From the Navajo Nation

Abstract

A substantial burden of stomach cancer continues to be observed in American Indians in the United States (US). The Navajo Nation, the largest American Indian tribe in the Southwestern US, is experiencing a higher incidence of stomach cancer compared to the general population in the region, possibly due to the high prevalence of Helicobacter pylori (H. pylori) infection, an infectious pathogen that colonizes the stomach and is a major risk factor for stomach cancer. To assess the prevalence, virulence, and risk factors for H. pylori infection in Navajo adults, we initiated a cross-sectional study in two geographic areas of the Navajo Nation. Study recruitment occurred from January to October 2021 during the COVID-19 pandemic. Participants were recruited using online and offline platforms, including social media, a study website, newspaper advertisements, flyers, word of mouth, and community outreach. Demographic, health, behavioral, environmental, and diet factors were assessed from health and food frequency questionnaires. H. pylori infection and cagA virulence were detected from stool samples by droplet digital PCR. Of 99 participants recruited, 56.6% (95% CI: 46.2–66.5) of participants were infected with H. pylori and, among H. pylori-infected participants, 78.6% (95% CI: 65.6–88.4) were infected with a cagA-positive H. pylori strain. Having a history of H. pylori infection was inversely associated with H. pylori infection (OR = 0.05, 95% CI: 0.01–0.34, P = 0.005), and using Navajo herbal medicine once a month was positively associated with H. pylori infection (OR = 7.28, 95% CI: 1.40–61.12, P = 0.03). No significant associations were observed with other risk factors (e.g., older age, males, lower education levels, smoking, alcohol use, and high sodium intake). The prevalence of H. pylori infection was two times higher in adults in the Navajo ABID study compared to the US population (27% seroprevalence), and the prevalence of the cagA gene in H. pylori-infected participants was four times higher than the US population cagA gene prevalence in White people (19% seroprevalence). These findings provide a greater understanding of the burden of H. pylori and cagA-positive infections and can inform prevention strategies to reduce H. pylori infections in the Navajo Nat.