Prevalence of Asthma Symptoms in Children and Adolescents in Karaj, Iran: A Report from the Global Asthma Network Phase I Study.

  This study is a part of the Global Asthma Network (GAN) phase I project to assess asthma symptoms in children, adolescents, and their parents in Karaj, Iran. The present cross-sectional study was conducted in 2019-2020 in Karaj, Iran, in alignment with the goals of the GAN study, including assessing asthma prevalence, severity, and risk factors. In this study, 1500 students were selected using a multistage stratified cluster sampling method from 40 public and private schools in Karaj. The entire population of children aged 6-7 years or adolescents aged 13-14 years in a given school and their parents was considered the sample unit. The GAN core questionnaires were completed for students and parents. The results showed that the response rate was 89.6%. A total of 1326 children and adolescents, 572 children aged 6-7 years, and 754 aged 13-14 years and their parents were enrolled in the study. The prevalence of ever- and current wheezing was 24% and 13.8% among 6-7-year-olds, and 18.8% and 12.3% among 13-14-year-olds, respectively. In children aged 6-7 years, parental wheezing significantly increased the chances of children wheezing (odds ratio: 3.27; 95% confidence interval: 1.70, 6.310). The current study's findings showed that the prevalence of asthma symptoms among children and adolescents and their parents in Karaj, Iran, was mainly higher than the findings of studies conducted in other cities in Iran.

Prevalence of Asthma Symptoms in 13-14-Year-Old Adolescents in Karaj.

Asthma is the most common chronic inflammatory respiratory disorder in children. This study was designed to assess the prevalence of asthma in 13-14-year-old adolescents in Karaj, Alborz province in Iran, using the international study of asthma and allergies in childhood (ISAAC) questionnaire. Totally 950 adolescents attending 40 schools located in 4 regions of Karaj city were enrolled in the survey. The Persian version of the ISAAC questionnaire was filled by 13-14-year-old students. Multi-stage clustered random sampling was used to divide the city of Karaj into four educational districts. Ever wheezing was reported in 22% of the individuals; 10.52% claimed to have wheeze in the last 12 months and 22.73% had during or after exercise. The experience of wheezing in the last 12 months was more prevalent among males (11.73% vs. 9.38%; p<0.05). However, having a history of asthma was higher among males (7.55% vs. 3.47%; p<0.05). History of hospitalization (60.8%), family history of asthma (49.4%), and history of food allergy (42.3%) were found to be the most frequent characteristics significantly associated with" ever wheezing" (p<0.05). The prevalence of wheezing in the last 12 months, as a major index of current asthma, was 10% which was close to the national average. However, nocturnal cough and exercise-induced wheezing were higher in Karaj compared to other cities of Iran; which could be related to the high level of air pollution in this industrial area.