Farm residence and exposures and the risk of allergic diseases in New Zealand children.
BACKGROUND
Studies in Europe have reported a reduced prevalence of allergy in farmers' children. We aimed to determine if there is a similar reduction in allergy among New Zealand farm children.


METHODS
Two hundred and ninety-three children participated (60%) aged 7-10 years, from selected schools in small towns and the surrounding rural area. Skin prick tests (SPT) to eight common allergens were performed. Parents completed questionnaires about allergic and infectious diseases, place of residence, exposure to animals, and diet, and they provided dust from the living-room floor. Endotoxin was measured using an Limulus amoebocyte lysate (LAL) assay and Der p 1 using enzyme-linked immunoassay (ELISA).


RESULTS
Current farm abode was found to increase the risk of having symptoms associated with allergy, but not SPT positivity. Independent inverse associations were found for early-life exposures: at least weekly consumption of yoghurt with hayfever (odds ratio (OR) = 0.3, 95% confidence intervals (CI) 0.1-0.7) and allergic rhinitis (OR = 0.3, 95% CI 0.2-0.7); any unpasteurized milk consumption with atopic eczema/dermatitis syndrome (AEDS) (OR = 0.2, 95% CI 0.1-0.8); cats inside or outside with hayfever (OR = 0.4, 95% CI 0.1-1.0) and AEDS (OR = 0.4, 95% CI 0.2-0.8); dogs inside or outside with asthma (OR = 0.4, 95% CI 0.2-0.8); and pigs with SPT positivity (OR = 0.2, 95% CI 0.1-0.9).


CONCLUSIONS
Despite finding a protective effect of early-life animal exposures, we found a greater prevalence of allergic disease on farms.
Wickens
K
K
Wellington Asthma Research Group, University of Otago, Wellington South, New Zealand.
Lane
J M
JM
Fitzharris
P
P
Siebers
R
R
Riley
G
G
Douwes
J
J
Smith
T
T
Crane
J
J
D000383:Agriculture; D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis; D000485:Allergens / Q000009:adverse effects / Q000032:analysis; D000818:Animals; D000829:Animals, Domestic / Q000276:immunology*; D039741:Antigens, Dermatophagoides / Q000009:adverse effects / Q000032:analysis; D060829:Arthropod Proteins; D002648:Child; D002669:Child Welfare; D003546:Cysteine Endopeptidases; D004731:Endotoxins / Q000009:adverse effects / Q000032:analysis; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D005192:Family Health; D005260:Female; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence; D012130:Respiratory Hypersensitivity / Q000453:epidemiology* / Q000209:etiology*; D012307:Risk Factors; D012423:Rural Health; D012572:School Health Services; D012882:Skin Tests; D013223:Statistics as Topic; D011795:Surveys and Questionnaires
D000393:Air Pollutants; D000485:Allergens; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D004731:Endotoxins; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1