Epidemiology and aetiology of chronic rhinosinusitis in Asia-A narrative review

Background Despite having a similar prevalence to Western populations, literature on chronic rhinosinusitis (CRS) in the Asian population is sparse. There is limited data on the epidemiology and aetiology of CRS in Asia. Objectives To review the current literature on the epidemiology and aetiology of CRS in Asia. Methods This is a narrative review of published data on the epidemiology and aetiology of CRS. Studies on CRS in Asian countries, published in English and indexed on PubMed or Google Scholar were reviewed. Where available, data extracted included epidemiology, endotype and cytokine profiles and genetic profiles. Results and Conclusion The prevalence of CRS in Asia ranges widely from 2.1% to 28.4%. Type 2 inflammation has been reported in 5%-55% of Asian patients, with lower levels of Type 2 cytokines reported in head to head comparisons of Western versus Asian patients. Notably, there exists marked heterogeneity in criterion of the tissue eosinophilic infiltration for diagnosis of type 2 CRS. Our review suggests that differences in prevalence of CRS and proportion of eosinophilic CRS between Asia and Europe and the Americas requires further study. Large-scale Asian studies utilising standardised definitions are needed to bridge this gap. Head to head genetic and microbiomal analysis may also be useful in understanding differences in CRS between the Asian and Western populations.