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Can selection explain the protective effects of farming on asthma?
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1
Department of Chemical and Biological Work Environment, STAMI National Institute of Occupational Health, Oslo, Norway
 
2
Centre for Public Health Research, Massey University, Wellington, New Zealand
 
3
Department of Public Health, Section for Environment, Work and Health, Aarhus University, Aarhus, Denmark
 
4
Department of Occupational Medicine, Aalborg University Hospital, Aalborg, Denmark
 
5
Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, United Kingdom
 
 
Ann Agric Environ Med. 2015;22(3):467-469
 
KEYWORDS
ABSTRACT
Introduction and objective:
Reduced asthma and allergy risks in farmers have been ascribed to microbial exposures. However, selection may also play a role and this was assessed in two Scandinavian farming populations.

Material and Methods:
Asthma prevalence in 739 Danish farming students was compared to that of 1,105 siblings. 8,482 Norwegian farmers were also compared with 349 early retired farmers.

Results:
The prevalence of ever-asthma was 5.4% in farming students and 5.2% in siblings (OR 1.1; 95%CI 0.73–1.7). Current asthma in farmers was 3.0% compared to 6.3% in farmers who had retired early (OR 1.8, 95%CI 1.1–2.9). Adjustments for early retirement increased the asthma prevalence by 0.3–0.6%. Farmers who had changed production were more likely to have asthma (OR 9.8, 95% CI 6.0–16).

Conclusions:
No healthy worker selection into farming was observed and changes in asthma prevalence due to early retirement were small. Selection effects are therefore unlikely to explain the protective effects of farming on asthma.

 
REFERENCES (11)
1.
von Mutius E. Asthma and allergies in rural areas of Europe. Proc Am Thorac Soc. 2007; 4(3): 212–216.
 
2.
Flohr C, Yeo L. Atopic dermatitis and the hygiene hypothesis revisited. In: Shiohara T (ed). Pathogenesis and management of Atopic Dermatitis. Curr Probl Dermatol, Basel, Karger. 2011; 41: 1–34.
 
3.
Omland Ø. Exposure and respiratory health in farming in temperate zones –a review of the literature. Ann Agric Environ Med. 2002; 9(2): 119–136.
 
4.
Ege MJ, Mayer M, Normand AC, Genuneit J, Cookson WO, Braun-Fahrländer C, Heederik D, Piarroux R, von Mutius E; GABRIELA Transregio 22 Study Group. N Engl J Med. 2011; 364(8): 701–709.
 
5.
Braun-Fahrländer C, von Mutius E. Can farm milk consumption prevent allergic diseases? Clin Exp Allergy. 2011; 41(1): 29–35.
 
6.
le Moual N, Kauffmann F, Eisen EA, Kennedy SM. The healthy worker effect in asthma: work may cause asthma, but asthma may also influence work. Am J Respir Crit Care Med. 2008; 177(1): 4–10.
 
7.
Omland Ø, Sigsgaard T, Hjort C, Pedersen OF, Miller MR. Lung status in young Danish rurals: the effect of farming exposure on asthma-like symptoms and lung function. Eur Resp J. 1999; 13(1): 31–37.
 
8.
Eduard W, Douwes J, Omenaas E, Heederik D. Do farming exposures cause or prevent asthma? Results from a study of adult Norwegian farmers. Thorax 2004; 59(5): 381–386.
 
9.
Dumas O, Smit LA, Pin I, Kromhout H, Siroux V, Nadif R, et al. Do young adults with childhood asthma avoid occupational exposures at first hire? Eur Respir J. 2011; 37(5): 1043–1049.
 
10.
Radon K, Schulze A, Nowak D. Inverse association between farm animal contact and respiratory allergies in adulthood: protection, underreporting or selection? Allergy 2006; 61(4): 443–446.
 
11.
Eduard W, Omenaas E, Bakke P, Douwes J, Heederik D. Atopic and non-atopic asthma in a farming and a general population. Am J Ind Med. 2004; 46(4): 396–399.
 
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