Clinical Characteristics, Lifestyle and Multi-omics Analysis in Autoimmune Gastritis

Inclusion Criteria: * Aged 35-75 years. * Type A atrophic gastritis: Underwent gastroscopy in hospitals mentioned above. Gastroscopy and histopathology showed no significant atrophy of antrum mucosa, but significant atrophy of the body or fundus mucosa, accompanied by positive blood and/or gastric fluid anti-parietal cell antibodies and/or anti-internal factor antibodies. No obvious tumor, deep ulcer, severe bile reflux, severe erosion, or active bleeding. Type B atrophic gastritis: Underwent gastroscopy in hospitals mentioned above. Gastroscopy and histopathological examination showed multifocal atrophy of gastric mucosa, mainly antrum involved. No obvious tumor, ulcer, moderate to severe bile reflux, moderate to severe erosion, multiple polyps (≥2) , or active bleeding. Chronic non-atrophic gastritis: Underwent gastroscopy in hospitals mentioned above. Gastroscopy and histopathology showed chronic inflammation of gastric mucosa with infiltration of lymphocytes and plasma cells, and no intrinsic glandular reduction. No obvious tumor, ulcer, moderate to severe bile reflux, moderate to severe erosion, multiple polyps (≥2) , or active bleeding. * Underwent colonoscopy within the past 5 years, and no obvious abnormalities such as inflammation, polyps, tumor, or ulcer were observed. * Have the cognitive level to understand the questionnaire and cooperate voluntarily. Exclusion Criteria: * Aged \<35 years or\>75 years. * Histopathology indicated dysplasia. * Long-term use of PP…