The Canadian asthma primary prevention study: outcomes at 2 years of age.
BACKGROUND
Avoidance of individual risk factors have not been successful in preventing the development of asthma.


OBJECTIVE
We sought to determine the effectiveness of a multifaceted intervention program in primary prevention of asthma in high-risk infants.


METHODS
We identified 545 high-risk infants on the basis of an immediate family history of asthma. Families were randomized into intervention or control groups. Intervention measures included avoidance of house dust mite, pet allergen, and environmental tobacco smoke. Breast-feeding was encouraged with formula supplementation if necessary, and introduction of solid foods was delayed.


RESULTS
At 2 years of age, 19.5% of the children had asthma, and 14.7% had atopy (positive skin test response to one or more common allergens). Significantly fewer children had asthma in the intervention group compared with in the control group (16.3% vs 23.0%), with 60% less persistent asthma at 2 years. There was a 90% reduction for recurrent wheeze in the intervention group compared with that seen in the control group. Exposure to maternal environmental tobacco smoke during pregnancy or the first year was a risk factor for asthma at 2 years of age. A positive skin test response, particularly to food, at 12 months predicted asthma at 2 years. There was no significant difference for atopy between the intervention and control groups, but daycare reduced atopy at 2 years.


CONCLUSIONS
This multifaceted intervention program during a window of opportunity in the first year of life was effective in preventing asthma in high-risk children at 2 years of age. Future studies with this cohort at school age are important.
Becker
Allan
A
Section of Allergy and Clinical Immunology, Department of Pediatrics and Child Health, University of Manitoba, AE101-671 William Avenue, Winnipeg, Manitoba R3E 0Z2, Canada.
Watson
Wade
W
Ferguson
Alexander
A
Dimich-Ward
Helen
H
Chan-Yeung
Moira
M
D000485:Allergens; D001249:Asthma / Q000453:epidemiology / Q000517:prevention & control*; D001362:Avoidance Learning; D001942:Breast Feeding; D002170:Canada / Q000453:epidemiology; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000517:prevention & control; D007223:Infant; D007231:Infant, Newborn; D015995:Prevalence; D012307:Risk Factors; D013997:Time Factors
D000485:Allergens