Purpose of the Study. Asthma eventually develops in only one third of atopic children. The aim of this study was to prospectively investigate the pattern of atopic sensitization typically associated with the development of asthma in childhood.
Study Population. A cohort of 1314 children followed from birth to the age of 7 years in the German Multicenter Allergy Study.
Methods. Parental questionnaires on asthma and asthmatic symptoms were completed 6 times up to the age of 2 years and from then on yearly. Determination of specific immunoglobulin E to 9 food and inhalant allergens was performed yearly, and at the age of 7 years, a bronchial histamine challenge was conducted.
Results. Onset of atopic sensitization in children with current asthma at the age of 7 years was significantly earlier than in children without current asthma (39.4% before age 1 year vs 21.0%; P = .015). Early atopic sensitization without any sensitization to inhalant allergens at the age of 7 years conferred no increased risk for asthma at this age. Only those children sensitized to inhalant allergens by the age of 7 years were at a significantly increased risk of being asthmatic at this age (odds ratio 10.12; 95% confidence interval [CI]: 3.81–26.88). However, even in this group of persistently sensitized children, the risk of being asthmatic at the age of 7 years was only increased if a positive parental history of asthma or atopy was present (OR: 15.56; 95% CI: 5.78–41.83), with the effect being strongest for maternal asthma.
Conclusion. The results indicate that an underlying factor pertaining to asthma and maternal transmission may determine both a certain pattern of sensitization and the expression of asthma.
Reviewer’s Comments. This study challenges our current understanding of the natural history of childhood asthma. The notion of a progressive atopic march assumes that early atopic sensitization to food allergens is a risk factor for subsequent inhalant sensitization, which, in turn, is regarded as a risk factor for the development of asthma. However, recent epidemiologic studies showed no consistent protective effect of reduced food or inhalant allergens, as well as no positive effect of increased inhalant allergen levels on the development of asthma. This study supports the hypothesis that the development of childhood asthma and atopy run in parallel if certain perinatal or hereditary influences prevail, rather than being subsequent stepping stones in a progressive atopic march.
- Copyright © 2002 by the American Academy of Pediatrics