Transient early wheeze is not associated with impaired lung function in 7-yr-old children

The aim of the present study was to analyse determinants of lung function in 7-yr-old children with different wheezing patterns (early, persistent and late onset) in a prospective cohort study. The German Multicentre Allergy Study (MAS) followed 1,314 children from birth onwards. Annual assessments included clinical check-ups, a structured interview and repeated measurement of specific immunoglobulins Ig(E) directed against food and inhalant allergens. At the age of 7 yrs, lung function was measured by body plethysmography in 800 children. Episodes of wheezing in the past 12 months ("current wheeze") were strongly associated with reduced lung function at age 7 yrs. Children with wheezing episodes only during the first 3 yrs of life showed a slight impairment in maximal expiratory flow when 50% of the forced vital capacity remains to be exhaled (98.9+/-24.2 versus 103.2+/-22.8% of the predicted value in children who never wheeze). Separate analysis of determinants of pulmonary function within these subgroups resulted in distinctly different patterns. Determinants of impaired lung function in the group of current wheezers were: time in years since first wheeze, a parental history of atopy, current sensitisation to indoor allergens, elevated cord blood IgE levels and a low ponderal index at birth. In the group of transient early wheezers, frequent lower respiratory tract infections early in life and maternal smoking during pregnancy were significant but weak determinants of impaired lung function. The present results indicate that determinants of pulmonary function in 7-yr-old children differ with respect to different wheezing phenotypes, demanding different therapeutic strategies. Although transient early wheezers were found to have normal-to-subnormal lung function, children with asthmatic symptoms (persistent and late-onset disease) at age 7 yrs already show significant impairment of expiratory flow volumes.