Paediatric asthma prevalence: The first national population-based survey in Iran

Background The actual prevalence of paediatric asthma as a worldwide chronic disease has been surveyed in developed countries. However, no sufficient survey has been conducted in most of the eastern developing countries. Herein, we took measures to evaluate the prevalence of paediatric asthma in Iran. Methods In this national cross-sectional study, the prevalence of asthma symptoms was estimated throughout the country using a randomized multistage stratified cluster sampling method in 16 410 and 16 850 individuals aged 6-7 and 13-14 years, respectively. A validated questionnaire including core questions of the International Study of Asthma and Allergies in Childhood (ISAAC) was applied between November 2015 and February 2016. Results The total prevalence of asthma was 10.9% (n = 3624) (95% confidence interval [CI]: 10.6%-11.2%) which was significantly higher among 13- to 14-year olds compared to a younger age group (12.4% vs. 9.4%, P < 0.001), males versus females (12.1% vs. 9.8%, P < 0.001) and residents of urban compared to rural areas (P = 0.003). The prevalence of severe asthma was 3.9%, being significantly more prevalent in higher age groups and male individuals (P < 0.001). A significant relationship was found between asthma and passive smoking in both 6- to 7- and 13- to 14-year olds (P < 0.001). Conclusions The prevalence of asthma and severe asthma in the paediatric population of Iran was similar to other developing countries. It is recommended to pay special attention to urban regions, male individuals and higher age groups for better controlling of asthma. Nevertheless, further national surveys are necessary to determine the trend of paediatric asthma in Iran.