Prevalence of coeliac disease in Northwest China: heterogeneity across Northern Silk road ethnic populations.

Background: Epidemiological data of coeliac disease are lacking from the central Asian region.

Aims: To verify the occurrence of coeliac disease amongst four major ethnic groups of Xinjiang Uyghur Autonomus Region, China.

Methods: 2277 in-patients with gastrointestinal symptoms (1391 Han, 608 Uyghur, 146 Kazakh and 132 Hui; mean age: 54 ± 12.8 years) were included. Total IgA, anti-deamidated gliadin peptide (DGP)-IgG, and anti-tissue transglutaminase (anti-tTG)-IgA were analysed. All antibody-positive subjects were further tested for endomysial (EMA) antibodies and were HLA genotyped. All subjects with antibody positivity were asked to undergo intestinal biopsy. In addition, a subset of antibody-negative subjects were tested for HLA-DQA1and DQB1.

Results: Among the 2277 subjects, 29 subjects were defined as coeliac disease autoimmune (positive results for anti-tTG IgA and EMA-IgA) (1.27%; 95% confidence interval, 0.81%-1.73%), eight of them underwent biopsy and all showed coeliac disease histology (0.35%; 95% Cl, 0.11%-0.59%). The frequency of coeliac disease autoimmunity was lowest among the Han (0.79%), followed by the Uyghur (1.81%), the Kazakh (2.05%) and the Hui (3.03%). The frequency of the HLA-DQ2 and/or DQ8 haplotype was highest in the Uyghur (52.1%), followed by the Hui (44.4%), the Kazakh (40.0%) and the Han (39.4%). Besides, a three times higher frequency of coeliac disease autoimmunity was found among rural living subjects with significantly higher wheat consumption compared to urban living subjects (3.16% vs 0.97%, P < 0.01).

Conclusions: In Xinjiang, coeliac disease does occur, especially in the rural area. The HLA haplotype and environment play key roles in the development of coeliac disease.