The Canadian Childhood Asthma Primary Prevention Study: outcomes
at 7 years of age
Chan-Yeung M, Ferguson A, Watson W, Dimich-Ward H, Rousseau
R, Lilley M, Dybuncio A, Becker A. J Allergy Clin Immunol.
2005 Jul;116(1):49-55.
Abstract
BACKGROUND: Avoidance of any one of the individual risk factors
associated with childhood asthma has not been successful
in preventing its development.
OBJECTIVE: The purpose of
this study is to determine the effectiveness of a multifaceted
intervention program for the primary prevention of asthma
in high-risk infants at 7 years of age.
METHODS: Five
hundred forty-five high-risk infants with an immediate family
history of asthma and allergies were prospectively randomized
into intervention or control groups prenatally. Intervention
measures introduced before birth and during the first year
of life included avoidance of house dust, pets, and environmental
tobacco smoke and encouragement of breast-feeding with delayed
introduction of solid foods. Assessment of outcomes at 7
years consisted of examination by pediatric allergists, methacholine
inhalation tests, and allergy skin tests.
RESULTS: At
7 years, 469 of the 545 children were contacted, and 380
returned for further assessment. The prevalence of pediatric
allergist-diagnosed asthma was significantly lower in the
intervention group than in the control group (14.9% vs 23.0%;
adjusted risk ratio, 0.44; 95% CI, 0.25-0.79). The prevalence
of allergic rhinitis, atopic dermatitis, atopy (defined as
positive skin test reactions to any common allergen), and
bronchial hyperresponsiveness (defined as the provocative
concentration of methacholine that induced a 20% decrease
in FEV 1 from a postsaline value of less than 7.8 mg/mL)
were not significantly different between the
2 groups. The
prevalence of asthma (defined as wheeze without colds and the
presence of bronchial hyperresponsiveness) was also significantly
lower in the intervention group compared with the control group
(12.9% vs 25.0%; adjusted risk ratio, 0.39; 95% CI, 0.22-0.71).
CONCLUSION: The multifaceted
intervention program was effective in reducing the prevalence
of asthma in high-risk children at 7 years of age.
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