Atopic and non-atopic asthma in a farming and a general population

Am J Ind Med. 2004 Oct;46(4):396-9. doi: 10.1002/ajim.20088.


Background: In a previous study inverse associations between asthma and exposure to fungal spores and endotoxins in atopic farmers and positive associations with the same factors in non-atopic farmers were documented. No external reference population had been included. We, therefore, compared this farming population with the general population from an adjacent region.

Methods: Random samples of a farming (n=2,106) and a rural (n=351) and urban (n=727) general population were selected. Atopy was assessed by serum IgE and asthma by questionnaires.

Results: The asthma prevalence was 4.0% among farmers, 5.7% in the rural, and 7.6% in the urban population. Atopy was similar (9-10%). Most asthmatics were not atopic, 67-75%. Farmers had asthma less often than the general population OR 0.52 (95% CI 0.36-0.75); both atopic (OR 0.33 (95% CI 0.15-0.69)) and non-atopic asthma (OR 0.60 (95% CI 0.39-0.93)).

Conclusion: This may indicate a protective effect of the farm environment on asthma but a healthy worker effect may also play a role.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Agricultural Workers' Diseases / epidemiology
  • Agricultural Workers' Diseases / etiology
  • Agricultural Workers' Diseases / immunology
  • Asthma / epidemiology*
  • Asthma / etiology
  • Asthma / immunology
  • Dermatitis, Atopic / epidemiology
  • Dermatitis, Atopic / etiology
  • Dermatitis, Atopic / immunology
  • Endotoxins / immunology
  • Environmental Exposure / adverse effects*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Norway / epidemiology
  • Occupational Exposure / adverse effects*
  • Prevalence
  • Rural Population
  • Spores, Fungal / immunology
  • Surveys and Questionnaires


  • Endotoxins