Abstract
Introduction: Wheeze, as suggestive of asthma, may follow various time courses during childhood. Incidence, remission and relapse rates are high. Compared to the pre-school ages, school age and adolescence have been less studied. The aim was to characterize temporal patterns of wheeze in school children.
Methods: At age 7-8 years, 3,430 (97% of invited) children in Northern Sweden completed ISAAC questionnaires. The same questions were used in 10 yearly follow-ups until age 17-18. Data from the 2,622 (76.4%) subjects that participated at 5 or more occasions were analysed.
Results: From age 7-8 to 17-18 one third reported wheezing at some occasion. Persistent wheeze from age 7-8 was reported by 2.9%. It was closely associated with rhino-conjunctivitis and parental asthma at age 7-8, RR 10 (6.6-15) and 5.3 (3.5-8.2). Incident wheeze persisting until age 17-18 was reported by 7.6%, while 2.6% had remittent wheeze, i.e. wheeze at age 7-8 but not at study end. Remittent wheeze was associated with respiratory infections before age 7-8, RR 4.1 (2.2-7.8). Transient wheeze for 1 years or more, not persisting until age 17-18, was seen in 8.7%. Of the 12.0% reporting intermittent periods of wheeze with no clear pattern, nearly half wheezed only at 1 or 2 occasions.
Discussion: In this large cohort of school children followed yearly by questionnaires, the majority of children with any wheeze during the school years were neither wheezing at age 7-8, nor at age 17-18. Half of the children wheezing at age 7-8 were in remission by age 17-18. Whereas wheeze associated with respiratory infections has a good probability of remission, heritability and concomitant allergic rhinitis predict persistence of wheeze.
- © 2011 ERS
