The Journal of Allergy and Clinical Immunology
Volume 111, Issue 1 , Pages 162-168, January 2003

Eighteen-month outcomes of house dust mite avoidance and dietary fatty acid modification in the childhood asthma prevention study (CAPS)☆☆☆

Westmead and Camperdown, Sydney, Australia

From athe Clinical Epidemiology Unit, The Children's Hospital, Westmead; bthe Department of Child Health and Paediatrics, University of Sydney; cthe Woolcock Institute of Medical Research, University of Sydney, and the Cooperative Research Centre for Asthma, Camperdown; dthe Department of Biochemistry, University of Sydney; ethe Centenary Institute of Cancer Medicine and Cell Biology and the Department of Medicine, University of Sydney; and fthe Faculty of Medicine, University of Sydney

Received 23 July 2002; received in revised form 27 September 2002; accepted 9 October 2002.

Abstract 

Background: Observational studies have linked house dust mite (HDM) exposure and dietary fatty acid intake with asthma in childhood. However, definitive evidence of their role in the etiology of asthma requires a randomized controlled trial. Objective: We hypothesized that the incidence of asthma and allergy in high-risk children would be reduced by avoidance of HDM allergens, supplementation with omega-3 fatty acids, or the combination of these strategies. We present the results of an interim analysis reporting outcomes assessed at 18 months. Methods: A total of 616 pregnant women were randomized to an HDM avoidance intervention, comprising the use of impermeable mattress covers and an acaricide or control and the use of an oil supplement, margarines, and cooking oils containing high levels of omega-3 fatty acids or control. Atopic status was measured by skin prick testing. Symptoms, diagnoses, and medication histories were elicited by means of parental interviews. Results: The diet intervention resulted in a 9.8% absolute reduction (95% CI, 1.5-18.1; P = .02) in the prevalence of any wheeze and a 7.8% absolute reduction (95% CI, 0.5-15.1, P = .04) in prevalence of wheeze of >1 week, but it had no effect on serum IgE, atopy, or doctors' diagnosis of asthma. The HDM avoidance intervention did not affect these outcomes but was associated with a lower use of oral steroids. Conclusion: Increasing dietary omega-3 fatty acids might have a beneficial effect on the prevalence of wheeze during the first 18 months of life. Follow-up to age 5 years, when the effect of the interventions on asthma risk will be assessed, is underway. (J Allergy Clin Immunol 2003;111:162-8.)

Keywords:  Allergen avoidance, asthma, atopy, fatty acids, house dust mite, primary prevention

Abbreviations:  HDM , House dust mite

 

☆ Supported in part by the National Health and Medical Research Council of Australia, New South Wales Health Department, The Children's Hospital at Westmead, and the Cooperative Research Centre for Asthma. Contributions of goods and services were made by Allergopharma Joachim Ganzer KG Germany, John Sands Australia, Hasbro, Refrigerated Roadways, and AstraZeneca. Goods were provided at reduced cost by Auspharm, Allersearch, Meadow Lea Foods, and Clover Corporation.

☆☆ Reprint requests: Seema Mihrshahi, MPH, Clinical Epidemiology Unit, The Children's Hospital at Westmead, Locked Bag 4001, Westmead, NSW 2145, Australia.

PII: S0091-6749(02)91298-4

doi:10.1067/mai.2003.36

The Journal of Allergy and Clinical Immunology
Volume 111, Issue 1 , Pages 162-168, January 2003

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