Demographics, risk factors and prevalence of chronic cough in Asian general adult population: a narrative review.

Background and Objective: Chronic cough is the most common medical problem for patients presenting to primary and secondary health care bringing a significant disease burden. Asia has the largest population size, with diverse cultures and environments. However, there is no comprehensive report of the prevalence, underlying causes, and disease burden of chronic cough among the general adult population in Asia. We therefore aimed to summarize the epidemiology of chronic cough in Asian general adult population. Methods: A narrative search of PubMed database, the Cochrane Library, and Web of Science was performed by using medical theme title as the main and supplemented by free text words including "chronic cough", "chronic bronchitis", "longstanding cough", "persistent cough", "epidemiology", "prevalence", "risk factor", "burden", "adult", "general population", and "Asia". Key Contents and Findings: An increasing number of studies on chronic cough prevalence in Asia focus primarily on East Asia, with limited attention to Central Asia. The prevalence among the general population reported in different regions of Asia varies widely, partly due to the use of variable definitions of chronic cough. Several risk factors for chronic cough have been identified, including age, allergy or asthma, smoking, occupational exposure, and air pollution, however, other possible factors such as ethnicity, sex, body weight, other concomitant diseases, socioeconomic status, education level, and diet remain inconclusive. Even if chronic cough is typically not life-threatening, the physical, psychological, and socioeconomic burden of chronic cough is obvious, especially for older patients or those with more comorbidities. Conclusions: Chronic cough is a common symptom in the Asian general adult population, which is related to several identifiable risk factors and leads to a great disease burden. In future research, there is an urgent need to apply the standard definition of chronic cough, and include some countries or regions to make up for the lack of chronic cough epidemiological data in Asia.