A systematic review of the evidence of outdoor air pollution on asthma hospital visits in children and adolescents in South Asia – a call for data

Abstract

Background: Outdoor air pollution and childhood asthma are increasing problems in South Asian countries. However, little is known about the associations between levels of air pollution and severe childhood asthma requiring hospital treatment in these regions. Methods: We undertook a systematic review to assess the evidence between outdoor air pollution exposure and childhood and adolescent asthma hospitalization in South Asia. MEDLINE, Web of Science, Google Scholar, CINAHL, Embase, Scopus, ProQuest Central databases were searched for peer-reviewed papers, and examination of reference lists was conducted for additional studies. We identified all the literature published in English up to January 2021 for the study population comprised of children aged less than 19 years. The search strategy was designed to identify all the studies and screen them as per the inclusion criteria. The method of qualitative synthesis using the standard tool determined the comprehensiveness of the assessment of bias. Results: Of the original 367 studies screened three studies were ultimately included from India, Pakistan and Sri Lanka and a narrative synthesis was conducted. Although studies reported adverse effects of outdoor pollution on asthma hospitalizations, limitations in exposure assessments, varying definitions of asthma hospitalizations and limited data analysis were identified. Conclusions: There is currently limited evidence that can provide meaningful risk estimates of the impact of outdoor air pollution on asthma hospitalizations during childhood and adolescence. Studies with comparable outcome definitions, appropriate exposure assessments and study designs are needed to inform future public and environmental health policy. PROSPERO registration: CRD42020156714 (28/04/2020)

Self-reported prevalence of asthma and its associated factors among adult rural population in Bangladesh: a cross-sectional study using WHO PEN protocol

“…40 While the prevalence of asthma in many developing countries of South Asia is increasing, very few studies determined the risk factors for this increase. 34 The prevalence of asthma increased with the increase of age among the respondents of this study. This study also found that the prevalence of asthma was quite high (6.0% or more) among those who were more than 60 years of age, ever smokers, underweight and those with comorbidities besides asthma or with family history of asthma.…”

“…While the prevalence of asthma in many developing countries of South Asia is increasing, very few studies determined the risk factors for this increase 34. The prevalence of asthma increased with the increase of age among the respondents of this study.…”

“…This was lower than the prevalence of 7% which was found in a recent study among people of all age groups (infants to adults) in a rural population of Bangladesh, 33 but higher than the overall prevalence of asthma in Asia which was found to be 3.5%, and is increasing over the years. 34 However, over the last few years, many studies noted a wide range of prevalence of asthma in South Asian countries, such as India (1.8–6.3%), 35 36 Bangladesh (1.59–10.7%), 34 36 Nepal (4.2–8.9%) 37 and Pakistan (1.8–3.7%). 38 39 Studies in developing countries of Africa suggested that the prevalence of asthma has been increasing over the last 20 years from 1990 to 2010.…”

Effects of Ambient Air Pollutants on Hospital Admissions among Children Due to Asthma and Wheezing-Associated Lower Respiratory Infections in Mysore, India: A Time Series Study

“…Asthma in children is an important global health burden [ 5 ]. Several environmental, individual, and familial factors are associated with hospitalisation for asthma in children [ 6 , 7 , 8 , 9 , 10 , 11 ]. Understanding the triggers for hospitalization is important, as a high rate of admissions is a burden on the individual, the carer, and the hospital system.…”