Diet Patterns and Helicobacter pylori on the Navajo Nation

Abstract

Introduction: Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects and colonizes the lining of the stomach. Approximately 50% of the global population has an active infection. Persistent infection is associated with the development of a variety of stomach pathologies, including non-cardia gastric cancer. Gastric cancer rates on the Navajo Nation are 4-times higher than that of non-Hispanic White populations living in the surrounding states. Certain dietary patterns have shown to be protective against gastric cancer and other gastrointestinal pathologies; specifically, diets high in green leafy vegetables and foods that are high in antioxidants, particularly citrus fruits. The goal of this research was to determine if there were associations between H. pylori infection and consumption of specific food groups, specifically green leafy vegetables, citrus fruits, traditional foods, and contemporary culturally specific food. Methods A cross-sectional study, Navajo Healthy Stomach Project, was conducted in Summer 2018 at three Navajo Nation chapters to study the prevalence of H. pylori in adults. The study included individual and household surveys and a 12-month food frequency questionnaire (FFQ) of 95 items. H. pylori infections were assessed using urea breath tests (UBT). Of the 101 participants, 94 completed both the UBT and the FFQ and are included in this current analysis. Food group consumption scores were created by averaging the reported usual consumption of specific food items for the following food categories: traditional Navajo foods, culturally specific foods, all fruits, citrus fruits, vegetables, and green leafy vegetables. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated using multiple logistic regression to determine associations between specific diet patterns and H. pylori infection with accounting for household clustering using STATA 16. Results The overall prevalence of H. pylori in this population was 64.9%. The most commonly consumed food categories with scores above 2, indicating consumption of at least once a month were citrus fruits, traditional food, fruits, and vegetables. The consumption of leafy green vegetables tended to be associated with 26% lower odds (95% CI: 0.20, 0.89) of having a positive UBT result. Fruits showed a protective, but not statistically significant, effect (OR= 0.67; 95% CI:0.35, 1.30). Citrus fruits similarly trended toward protective (OR=0.71 95% CI: 0.49, 1.05) in the final adjusted model. Cultural foods and traditional foods had ORs of 0.72 (95% CI: 0.37, 1.42) and 0.84 (95% CI: 0.41, 1.68), respectively, but the results were not statistically significant. Conclusion The trends uncovered in this study show that consumption of green leafy vegetables and citrus fruits in diets should continue to be investigated to determine the association between consumption and risk of H. pylori infection. The small sample size of this pilot study impacted the power of this study and contributed to the lack of statistically significant findings. With the expansion of the project to new locations, more data will be collected, and the effects of traditional food and citrus fruit consumption can be more deeply explored.