Reduced risk of atopic sensitization among farmers: the Humboldt study.
BACKGROUND
It needs to be clarified whether farming is associated with a reduced risk of atopy or allergic condition. There is a lack of consistent evidence for prevalences of atopy, respiratory allergy and asthma in adult farmers.


METHODS
A cross-sectional study of adults (n = 2,081) was conducted in the town of Humboldt, Sask. Allergy skin prick tests were conducted to determine atopic sensitization. Respiratory allergy and physician-diagnosed asthma were based on self-reporting. Logistic regression was used to assess the associations of atopy, respiratory allergy and asthma with farming practices, adjusting for other important variables.


RESULTS
Of 2,081 participants, 27.8% were farmers. Reduced risks of atopic sensitization, respiratory allergy and asthma were observed among farmers compared to non-farmers. After adjustment for sex and age, which are major confounders, the odds ratio for atopic sensitization was 0.79 (95% confidence interval: 0.65, 0.97) for farmers versus non-farmers. Asthma showed a similar trend; however, there was no statistically significant difference in either respiratory allergy or asthma rates observed between farmers and non-farmers.


CONCLUSIONS
The prevalence of atopy was lower in adult farmers than in non-farmers.
Chen
Yue
Y
Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ont., Canada. ychen@uottawa.ca
Rennie
Donna
D
Cormier
Yvon
Y
McDuffie
Helen
H
Pahwa
Punam
P
Dosman
James
J
D000328:Adult; D000383:Agriculture; D000485:Allergens / Q000009:adverse effects / Q000276:immunology; D001249:Asthma / Q000453:epidemiology*; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology*; D008297:Male; D015995:Prevalence; D012130:Respiratory Hypersensitivity / Q000453:epidemiology*; D012882:Skin Tests
D000485:Allergens