Purpose of the Study. To evaluate the effects of a multifaceted intervention program involving high-risk infants on the development of asthma at 7 years of age.
Study Population. Of the original 545 high-risk infants in the Canadian Childhood Asthma Primary Prevention Study, 380 were evaluated at 7 years of age. Infants at high risk for asthma development were defined as those with at least 1 first-degree relative with asthma or 2 first-degree relatives with other immunoglobulin E–mediated allergic diseases.
Methods. The initial 545 high-risk infants were randomly assigned before birth to a multifaceted intervention group (n = 279) or the control group (n = 266). The multifaceted intervention program, which was implemented before birth and during the first year of life, included house dust mite–control measures, pet-avoidance measures, avoidance of environmental tobacco smoke, breastfeeding, and/or using partially hydrolyzed whey formula. This study describes the follow-up assessment of 380 subjects at 7 years of age who completed a questionnaire and were evaluated by a pediatric allergist for asthma. Allergy skin testing and methacholine challenge were also performed.
Results. A significantly lower number of subjects had pediatric allergist–diagnosed asthma in the intervention group (14.9%) than in the control group (23.0%; adjusted relative risk [RR]: 0.44). The prevalence of asthma, defined as wheeze plus bronchial hyperreactivity (methacholine challenge), was also significantly lower in the intervention group when compared with the control group (12.9% vs 25%, respectively; adjusted RR: 0.39). There was no significant difference in the diagnosis of allergic rhinitis or atopic dermatitis, allergen skin-test reactivity, or bronchial hyperreactivity alone between the 2 groups. Symptoms of wheeze and wheeze apart from colds in the last 12 months were significantly lower in the intervention group compared with the control group. There were no significant differences in nocturnal symptoms, exercise-related symptoms, medication use, emergency visits for wheeze, nasal symptoms, or skin rash.
Reviewer Comments. Asthma and allergic diseases likely result from a combination of environmental and genetic factors. This study showed that the prevalence of asthma was decreased after an intervention program implemented early in life. Thus, recommending environmental controls as a safe method to decrease the risk of developing asthma in high-risk patients is reasonable. It is unclear from this study whether a specific environmental control or a combination of interventions is more effective. It is interesting that no difference was noted in the prevalence of allergic rhinitis or atopic dermatitis between the groups, which, theoretically, could also be affected by environmental controls.
- Copyright © 2006 by the American Academy of Pediatrics