Prevalence and Severity of Asthma Symptoms in Children of Tehran- International Study of Asthma and Allergies in Childhood (ISAAC).

This descriptive study was conducted to determine the prevalence of asthma and related symptoms among 6-7 and 13-14 year old school children in Tehran as a part of International study of Asthma and Allergies in childhood (ISAAC) phase III. The ISAAC written questionnaire was given to a total of 6127 students of 72 schools in urban area of Tehran. Simple random sampling was performed with a uniform distribution throughout 12 clusters of 2 divisions of the municipality. All 6-7 and 13-14 year old students were enrolled in this study. Results showed that 15% of the 6-7 year olds and 17% of the 13-14 year olds had positive history of wheezing among which 8.6% and 10.6% respectively had had recent attacks. Physician confirmed asthma was reported in 2.1% of the 6-7 year olds and 2.6% of the 13-14 age group. Severity of asthma assessed by frequency of speech limitation due to wheeze was positive in 1.5% of 6-7 aged group and 3% of 13-14 year olds. Exercise induced wheeze was detected in 2.3% of the 6-7year old group compared to 15.3% of the 13-14 year olds. Nocturnal cough was more prevalent among 13-14 year olds (18.4%) compared to only 7.2% in the 6-7 year olds. Overall, no significant change in prevalence of asthma symptoms has occurred since 1997 (the last phase of ISAAC) among children of Tehran. The results of our study suggest higher rates of confirmed asthma among 6-7 years old girls compared to boys. However, more extensive and precisely designed studies are needed to further confirm these findings.