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


CONCLUSIONS
This may indicate a protective effect of the farm environment on asthma but a healthy worker effect may also play a role.
Eduard
Wijnand
W
National Institute of Occupational Health, Oslo, Norway. Winjuad.Eduard@stami.no
Omenaas
Ernst
E
Bakke
Per Sigvald
PS
Douwes
Jeroen
J
Heederik
Dick
D
D000328:Adult; D000367:Age Factors; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000453:epidemiology / Q000209:etiology / Q000276:immunology; D001249:Asthma / Q000453:epidemiology* / Q000209:etiology / Q000276:immunology; D003876:Dermatitis, Atopic / Q000453:epidemiology / Q000209:etiology / Q000276:immunology; D004731:Endotoxins / Q000276:immunology; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects*; D015995:Prevalence; D012424:Rural Population; D013172:Spores, Fungal / Q000276:immunology; D011795:Surveys and Questionnaires
D004731:Endotoxins