Prevalence of asthma symptoms, diagnosis, and treatment in 12-14 year old children across Great Britain (international study of asthma and allergies in childhood, ISAAC UK)
Authors: B. Kaur, H R. Anderson, J. Austin, M. Burr, L. S Harkins, D. P Strachan, J. O Warner
Journal: BMJ (1998)

<b>Objective:</b> To investigate variations in the prevalence of self reported symptoms, diagnosis, and treatment of asthma in 12–14 year old children. <b>Design:</b> Self completion questionnaire. <b>Setting:</b> Great Britain. <b>Subjects:</b> All pupils aged 12–14 years in a stratified cluster sample of 93 large mixed secondary schools in 1995. <b>Main outcome measures:</b> Self reported prevalence of symptoms, diagnosis, and treatment of asthma at four geographical levels. <b>Results:</b> 27 507 questionnaires were completed (85.9% response rate). The national 12 month prevalence of any wheezing, speech limiting wheeze, four or more attacks of wheeze, and frequent night waking with wheeze was 33.3% (n=9155), 8.8% (2427), 9.6% (2634), and 3.7% (1023) respectively. The prevalence of ever having had a diagnosis of asthma was 20.9% (5736). In total, 19.8% (5438/27 507) of pupils reported treatment with anti-asthma drugs in the past year, but, of pupils reporting frequent nocturnal wheeze in the past year, 33.8% (342/1012) had no diagnosis of asthma and 38.6% (395/1023) denied receiving inhaler therapy. The 12 month prevalence of wheeze was highest in Scotland (36.7%, 1633/4444), but in England and Wales there was no discernible north-south or east-west gradient. Wheeze prevalence was slightly higher in non-metropolitan areas (35.0%, 6155/17 605) than in metropolitan areas (30.3%, 3000/9902). The prevalence of self reported asthma diagnosis and inhaler use showed no discernible national, regional, north-south, or east-west geographical pattern but was higher in non-metropolitan areas. <b>Conclusion:</b> Prevalence of self reported symptoms, diagnosis, and treatment of asthma was high among 12–14 year olds throughout Great Britain with little geographical or urban-rural variation. Underdiagnosis and undertreatment were substantial. <h3>Key messages</h3> We investigated the prevalence of self reported symptoms, diagnosis, and treatment of asthma in 12–14 year old children in Great Britain A third of subjects reported wheezing in the past year, and a fifth reported ever having had a diagnosis of asthma—higher prevalences than reported previously Prevalences of symptoms generally varied by a factor of 1.3 or less across Great Britain but, in contrast to previous reports, were significantly higher in Scotland than England and in non-metropolitan areas than metropolitan ones Asthma may still be undiagnosed and undertreated—4% of pupils reported having had a diagnosis of asthma but were still experiencing moderate or greater disruption of their lives, while 1-3.4% reported moderate to severe symptoms but were undiagnosed and untreated The limited geographical variation in prevalences of symptoms and diagnosis of asthma suggests that the causes of asthma are widely distributed in Great Britain and that factors which do vary geographically—such as climate, diet, and outdoor environment—are not the main determinants of prevalence.