Trends in asthma prevalence and severity in Omani schoolchildren: Comparison between ISAAC phases I and III

Background and objective: This study evaluated changes in the prevalence of asthma symptoms and asthma severity in Omani school children over time. Methods: Two cross-sectional surveys, in 1995 and 2001, were conducted as part of the International Study of Asthma and Allergies in Children on Omani schoolchildren in two different age groups (6-7 and 13-14 years). Results: There were 7067 children surveyed in 1995 (3893 in the younger and 3174 in the older group) and 7879 in 2001 (4126 in the younger and 3753 in the older group). Over the 6 years there was a significant increase in the prevalence of current wheeze 'any wheeze during the past 12 months' (from 7.1% to 8.4%; P = 0.035) in the younger group with no significant change in asthma diagnosis (10.5% vs 10.6%) or any other asthma symptoms. In the older group, all asthma symptoms remained unchanged except speech-limiting wheeze which declined from 4.0% to 2.8% (P = 0.007). In both surveys, more than 60% of current wheezers reported severe asthma symptoms, while only 60% of these reported a diagnosis of asthma. Conclusion: The prevalence of both asthma and severe asthma remains high among Omani children. There is significant 'under-diagnosis' and/or 'under-treatment' of asthmatic children which requires urgent evaluation and intervention.