Gradient disparities in allergy and the gut microbiome among rural, migrant, and urban populations across China

Abstract

Background

While much of the evidence linking the rapid urbanization and the increasing prevalence of allergen sensitization, but little is known regarding rural-to-urban migrants. The aim of this study was to identify the disparities in allergy, the gut microbiome and factors among native urban, migrating, and native rural Chinese.

Methods

We redesigned the dataset of the China Alliance of Research on Respiratory Allergic Disease secondary survey, and after stratified sampling, a subsample of 2422 subjects were enrolled for the analysis of a questionnaire, skin prick tests (SPT), and specific immunoglobulin E (sIgE) titer measurements against 8 common allergens. Fecal microbiotal composition was also sequenced by 16S rRNA and regression-based analyses with covariate adjustment applied.

Results

From urban to migrant and rural populations, IgE sensitization was predominantly directed against Dermatophagoides pteronyssinus (Der p). The titers of Der p-sIgE decreased sequentially across the 3 respective populations and co-sensitization to other allergens also showed a sequential decrease. Rural-to-urban migrants showed a low prevalence of Der p-SPT and Der p-sIgE initially, but developed substantial IgE titers and their gut microbiotal diversity, as well as species richness, appeared to change along with residential time spent in the urban area. High-fat diet, using a mattress, an SPT wheal size from Der p ≥ 6 mm, and duration of immigration >5 years were significantly associated with sIgE positivity in the migrants.

Conclusion

The Der p-sIgE responses and the composition of gut microbiota differs synchronously with extended living time in an urban area. Studies in immigrants provide a unique opportunities to evaluate the effects of environmental factors in the pathogenesis of allergic disorders.