Objective To investigate the positivity rates of specific antibodies, including parietal cell antibody (PCA) and anti-inner factor antibody (IFA), in a community population in Xinjiang for autoimmune gastritis (AIG), determine the prevalence of AIG, and analyze the correlations of PCA and IFA with clinical characteristics, pepsinogen (PG), gastrin 17 (G17), and Helicobacter pylori antibody (Hp-Ab).

Methods A cross-sectional survey was conducted using stratified random cluster sampling in community populations across 10 regions of Xinjiang from January 2022 to December 2023. General information was collected via a self-designed questionnaire, and fasting venous blood samples were obtained to measure laboratory parameters including PCA, IFA, PG Ⅰ, PG Ⅱ, PG Ⅰ/PG Ⅱ ratio, and G17. The positivity rates of PCA and IFA and the prevalence of AIG were calculated. Spearman correlation analysis was used to assess the relationships of PCA and IFA with PG Ⅰ, PG Ⅱ, PG Ⅰ/PG Ⅱ ratio, and G17. The diagnostic efficacy of PCA and IFA for atrophic gastritis was evaluated using receiver operating characteristic (ROC) curves, and multivariate logistic regression analysis was performed to identify factors influencing PCA and IFA positivity.

Results A total of 2018 community participants were included, comprising 972 males (48.17%) and 1046 females (51.83%), with a mean age of 42±19 years. The predominant ethnic groups were Han (42.22%) and Kazakh (33.10%). Hp-Ab positivity was observed in 1244 cases (61.65%). Serological criteria for atrophic gastritis were met in 56 cases (2.78%). PCA positivity was found in 253 cases (12.54%), IFA positivity in 30 cases (1.49%), and dual positivity in 11 cases (0.55%). A total of 617 participants (30.57%) voluntarily underwent endoscopic examination, among whom 7 cases (1.13%) were histopathologically confirmed as AIG. Positivity rates for PCA and IFA varied among ethnic groups, with the highest rates observed in the Kirgiz population (23.53% and 5.88%, respectively). Spearman correlation analysis revealed that PCA was negatively correlated with the PG Ⅰ/PG Ⅱ ratio (r=-0.051, P=0.022), while IFA was negatively correlated with PG Ⅰ(r=-0.069, P=0.002) and G17(r=-0.103, P < 0.001). Using PG Ⅰ/PG Ⅱ≤3.0 and PG Ⅰ≤70 μg/L as serological diagnostic criteria for atrophic gastritis, both PCA and IFA demonstrated poor diagnostic value for the condition. Multivariate logistic regression analysis identified age≥41 years (OR=2.278, 95% CI: 1.705-3.043, P < 0.001), history of allergies (OR=1.528, 95% CI: 1.002-2.331, P=0.049), and previous thyroid disease (OR=2.189, 95% CI: 1.451-3.300, P < 0.001) as independent risk factors for PCA positivity, while a history of alcohol consumption (OR=0.468, 95% CI: 0.260-0.842, P=0.011) was identified as a protective factor.Age≥41 years (OR=9.202, 95% CI: 2.168-39.052, P=0.003) was an independent risk factor for IFA positivity.

Conclusions The positivity rate of PCA is relatively high in the community population in Xinjiang and varies across different ethnic groups, whereas the positivity rate of IFA is lower than that of PCA. Age, history of alcohol consumption, history of allergies, and history of thyroid disease are associated with PCA positivity, while no correlation was found between Hp-Ab and PCA or IFA. The prevalence of histopathologically confirmed AIG among participants undergoing endoscopic examination is 1.13%.