Brunekreef B, Von Mutius E, Wong GK, Odhiambo JA, Clayton TO. Early life exposure to farm animals and symptoms of asthma, rhinoconjunctivitis and eczema: an ISAAC Phase Three Study.
Int J Epidemiol 2012;
41:753-61. [PMID:
22287135 DOI:
10.1093/ije/dyr216]
[Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND
Associations between early life exposure to farm animals and respiratory symptoms and allergy in children have been reported in developed countries, but little is known about such associations in developing countries.
OBJECTIVE
To study the association between early life exposure to farm animals and symptoms of asthma, rhinoconjunctivitis and eczema in a worldwide study.
METHODS
Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC) was carried out in 6- to 7-year-old children in urban populations across the world. Questions about early life exposure to farm animals (at least once/week) were included in an additional questionnaire. The association between such exposures and symptoms of asthma, rhinoconjunctivitis and eczema was investigated with logistic regression. Adjustments were made for gender, region of the world, language, gross national income and 10 other subject-specific covariates.
RESULTS
A positive association was found between early exposure to farm animals and the prevalence of symptoms of asthma, rhinoconjunctivitis and eczema, especially in non-affluent countries. In these countries, odds ratios (ORs) for 'current wheeze', 'farm animal exposure in the first year of life' and 'farm animal exposure in pregnancy' were 1.27 [95% confidence interval (CI) 1.12-1.44] and 1.38 (95% CI 1.21-1.58), respectively. The corresponding ORs for affluent countries were 0.96 (95% CI 0.86-1.08) and 0.95 (95% CI 0.84-1.08), respectively.
CONCLUSION
Exposure to farm animals during pregnancy and in the first year of life was associated with increased symptoms of asthma, rhinoconjunctivitis and eczema in 6- to 7-year-old children living in non-affluent but not in affluent countries.
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