Environmental and occupational respiratory disorders
Omega-3 and omega-6 fatty acid exposure from early life does not affect atopy and asthma at age 5 years

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Background

The Childhood Asthma Prevention Study was a randomized controlled trial conducted in children with a family history of asthma in whom omega-3 fatty acid supplementation and restriction of dietary omega-6 fatty acids did not prevent asthma, eczema, or atopy at age 5 years.

Objective

We sought to examine the relation of all measures of omega-3 and omega-6 polyunsaturated fatty acids with outcomes at age 5 years in the whole birth cohort, regardless of randomization group.

Methods

Plasma fatty acids were measured at 18 months, 3 years, and 5 years. Compliance with the fatty acid supplements was estimated every 6 months. Dietary intake was assessed at 18 months by means of weighed-food record and at 3 years by means of food-frequency questionnaire. At age 5 years, 516 children were examined for wheeze and eczema (questionnaire) and atopy (skin prick tests, n = 488). Multiple logistic regression was used to evaluate associations between exposures and outcomes.

Results

Plasma levels of omega-3 or omega-6 fatty acids were not associated with wheeze, eczema, or atopy at age 5 years (P = .11-.96). Overall, fatty acid exposure, measured as plasma levels, dietary intake, and compliance with supplements, was not associated with any respiratory or allergic outcomes (P = .35-.59).

Conclusion

This observational analysis of the cohort, using the full range of observed variation in omega-3 and omega-6 fatty acid exposure, supports the negative findings of the randomized controlled trial.

Clinical implications

Modification of dietary polyunsaturated fatty acids in early childhood is not helpful in preventing atopy and asthma.

Section snippets

Study design and subjects

CAPS is a randomized controlled trial designed to test the effectiveness of interventions to reduce house dust mite levels and to increase the intake of omega-3 fatty acids through a supplement, both separately and in combination, on the presence of asthma and allergic diseases. The design of the study, sample recruitment, criteria for inclusion, and data collection procedures have been described in detail elsewhere.10 In brief, pregnant women whose unborn child had at least 1 parent or sibling

Results

Outcome data at age 5 years were available for 516 participants (83.8% of the 616 randomized subjects). Of these, 375 (72.6%) completed the spirometry, and 488 (94.6%) had skin prick tests. Blood samples were taken from 393 (71.5%) at 18 months, 400 (75.5%) at 3 years, and 396 (76.7%) at 5 years. WFRs were available for 424 (77.1%) subjects at 18 months, and FFQs were completed by 456 (86.0%) subjects at 3 years. Compliance information was available for all 516 children at 5 years. Complete

Discussion

We found no association between plasma levels of omega-3 or omega-6 polyunsaturated fatty acids at 18 months, 3 years, and 5 years and the prevalence of asthma or wheezing illness, eczema, or atopy at 5 years. Furthermore, the overall effect of omega-3 and omega-6 fatty acids, based on information about plasma levels, intake from supplements, and intake from diet revealed no association with these clinical outcomes. These negative results strengthen the main result from the randomized

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Supported by the National Health and Medical Research Council of Australia, the Cooperative Research Center for Asthma, the New South Wales Department of Health, and the Children's Hospital at Westmead. Catarina Almqvist was funded by the Swedish Heart Lung Foundation and the Swedish Society of Medicine. Frances Garden was funded through the NSW Biostatistical Officer Training Program, NSW Department of Health. Contributions of goods and services were made by Allergopharma Joachim Ganzer KG Germany, John Sands Australia, Hasbro, Toll Refrigerated, AstraZeneca Australia, and Nu-Mega Ingredients Pty Ltd. Goods were provided at reduced cost by Auspharm, Allersearch, and Goodman Fielder Foods.

Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest.

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