Table 3

Associations between asthma and atopy and annual average exposure levels in a farming population (n = 1614)

FactorORadj of risk factor*
Asthma (n = 164)Atopy (n = 264)Asthma in atopic farmers† (n = 33)Asthma in non-atopic farmers (n = 131)
Results of a model with farm production and single exposure models are shown. Associations with asthma are also shown for atopic (n = 264) and non-atopic (n = 1350) individuals separately. The ORs of potential confounders were similar to table 2 (not shown).
*Adjusted by logistic regression.
†Only significant potential confounders were included in this model.
Farm production
    Crop1111
    Poultry1.2 (0.64 to 2.3)1.3 (0.72 to 2.2)1.2 (0.37 to 4.0)0.90 (0.43 to 1.9)
    Sheep/goats1.1 (0.52 to 2.5)1.0 (0.47 to 2.1)0.59 (0.23 to 1.5)1.6 (0.69 to 3.9)
    Cattle1.8 (1.1 to 2.8)1.2 (0.80 to 1.8)0.58 (0.27 to 1.3)1.5 (0.88 to 2.6)
    Swine1.6 (1.0 to 2.5)0.84 (0.54 to 1.3)0.54 (0.19 to 1.6)2.0 (1.2 to 3.3)
Total dust (mg/m3)
    0–1.81111
    1.9–2.60.88 (0.57 to 1.4)0.98 (0.70 to 1.4)0.84 (0.36 to 2.0)0.89 (0.53 to 1.5)
    2.7–8.01.2 (0.82 to 1.9)0.89 (0.63 to 1.3)0.38 (0.13 to 1.1)1.6 (1.0 to 2.6)
Fungal spores (106/m3)
    0–1.61111
    1.7–3.41.3 (0.82 to 1.9)0.98 (0.70 to 1.4)0.55 (0.23 to 1.3)1.6 (0.96 to 2.6)
    3.5–381.2 (0.77 to 1.8)0.99 (0.70 to 1.4)0.28 (0.10 to 0.78)1.7 (1.0 to 2.7)
Bacteria (106/m3)
    0–9.11111
    9.2–140.92 (0.60 to 1.4)0.91 (0.65 to 1.3)0.63 (0.26 to 1.5)1.0 (0.62 to 1.7)
    15–941.2 (0.78 to 1.8)0.74 (0.52 to 1.0)0.54 (0.20 to 1.4)1.5 (0.93 to 2.3)
Endotoxins (103 EU/m3)
    0–261111
    27–600.97 (0.62 to 1.5)1.1 (0.76 to 1.5)0.55 (0.23 to 1.3)1.1 (0.67 to 1.9)
    61–1401.2 (0.78 to 1.8)0.82 (0.58 to 1.2)0.34 (0.12 to 0.95)1.6 (0.99 to 2.5)
Ammonia (ppm)
    0–4.21111
    4.3–101.2 (0.81 to 1.9)0.93 (0.67 to 1.3)0.87 (0.38 to 2.0)1.4 (0.84 to 2.2)
    11–231.3 (0.87 to 2.1)0.92 (0.65 to 1.3)0.31 (0.10 to 0.95)1.8 (1.1 to 3.0)