Abstract
BACKGROUND: Autoimmune gastritis (AIG) is a risk factor for gastric neuroendocrine tumor (NET). We compared risk factors between AIG cases, non-autoimmune atrophic gastritis (NAIG) cases, and normal controls and determined the incidence of gastric malignancy, including adenocarcinoma and NET. METHODS: We included patients who underwent endoscopy with gastric biopsy between 3/2006 and 9/2021 in Harris Health (Houston, Texas). We identified AIG cases, NAIG cases (gastric atrophy or intestinal metaplasia [GIM] without autoimmune features), and normal controls (without AIG, NIAG, and GIM). A GI pathologist confirmed AIG diagnosis on histopathology report or slide. We determined risk factors of AIG compared to NAIG cases and normal controls and compared gastric malignancy incidence. RESULTS: We included 158 AIG cases, 445 NAIG cases, and 2389 controls. Compared to NAIG cases, male sex (adjusted odds ratio [OR] 0.33; 95% confidence interval [CI] 0.21-0.51), current tobacco use (adj OR 0.29; 95% CI 0.14-0.61), and H. pylori (adj OR 0.35; 95% CI 0.24-0.53) were inversely associated with AIG. Anti-parietal cell antibody positivity and elevated gastrin level were associated with AIG. Compared to normal controls, Hispanic and Asian race/ethnicity and age > 40 were associated with AIG. The risk of gastric malignancy, particularly NET, was 2.7-fold higher with AIG compared to NAIG. CONCLUSIONS: We found several risk factors (age, non-white race, female sex, non-tobacco user, lack of H. pylori) to be associated with AIG. The risk of gastric malignancy was elevated in AIG compared to NAIG which already is a precancerous condition. Early identification of AIG is important for cancer screening.