prevalence of asthma, copd, and chronic bronchitis in iran: a systematic review and meta-analysis

In this study, we aimed to conduct a meta-analysis on the results of eligible studies to estimate the prevalence of asthma, copd, and chronic bronchitis in iran. international and iranian databases including pubmed, scopus, web of science, iranmedex, and scientific information database (sid) were searched for population–based studies that had reported the prevalence of asthma and copd from 1990 to 2015. we conducted the meta-analysis using metaprop application of stata statistical software. i-squared was used for calculating heterogeneity among the studies. to determine causes of heterogeneity, subgroup analysis and meta-regression method were used. based on the results of random effect method, the overall prevalence of asthma ever was 4.56% (3.76%-5.36%) among men while it was 4.17% (3.42%-4.91%) among women. pooled prevalence of current asthma was 7.95% while confidence interval changed from 5.85% to 10.06% (men 5.83% (2.75%-8.92%), women 9.13% (3.35%-14.94%)). also based on the results of random effect model pooled prevalence of chronic bronchitis of five studies was 5.57%. it seems that the total crude prevalence of current asthma in iran is less than many other countries such as kuwait, lebanon, thailand, japan, australia and germany and is higher than some other countries such as oman, pakistan, south korea, india, china, taiwan, indonesia, spain, russia, and greece. on the other hand, iran is in middle situation in terms of the prevalence current asthma. our results can fill the information and knowledge gaps about the status of the prevalence of respiratory diseases in iran.