Comparison of characteristics of responders and nonresponders on exposure variables and electronic medical records (EMRs)
| Responders | Nonresponders | Unadjusted OR (95% CI) | Adjusted OR (95% CI) | |
| Subjects n | 14 875 | 12 969 | ||
| Age years# | 50.4±13.3 | 42.8±13.6 | 1.51 (1.48–1.53) | 1.52 (1.49–1.54) |
| Female | 53.2 | 45.4 | 1.48 (1.41–1.55) | 1.54 (1.47–1.62) |
| Exposure | ||||
| Distance to the nearest farm m¶ | 475±281 | 498±287 | 0.97 (0.96–0.98) | 0.97 (0.96–0.98) |
| Number of livestock farms | ||||
| Within 500 m | 1.5±1.9 | 1.4±1.8 | 1.03 (1.02–1.05) | 1.04 (1.02–1.05) |
| Within 1000 m | 8.1±5.7 | 7.4±5.4 | 1.02 (1.02–1.03) | 1.02 (1.02–1.03) |
| Presence of farm animals within 500 m | ||||
| Pigs | 25.1 | 23.0 | 1.12 (1.06–1.19) | 1.09 (1.02–1.17) |
| Poultry | 15.7 | 14.9 | 1.06 (0.99–1.13) | 1.03 (0.95–1.11) |
| Cattle | 44.5 | 41.3 | 1.14 (1.09–1.19) | 1.10 (1.04–1.16) |
| Goats | 1.7 | 1.3 | 1.27 (1.05–1.55) | 1.16 (0.94–1.44) |
| Mink | 1.7 | 1.6 | 1.06 (0.88–1.27) | 1.03 (0.85–1.25) |
| Presence of farm animals within 1000 m | ||||
| Pigs | 74.7 | 71.6 | 1.17 (1.11–1.24) | 1.11 (1.04–1.19) |
| Poultry | 59.0 | 55.5 | 1.15 (1.10–1.21) | 1.09 (1.04–1.16) |
| Cattle | 89.2 | 87.4 | 1.20 (1.12–1.29) | 1.06 (0.97–1.16) |
| Goats | 10.1 | 8.1 | 1.27 (1.17–1.38) | 1.23 (1.12–1.34) |
| Mink | 7.1 | 6.9 | 1.04 (0.95–1.14) | 0.99 (0.89–1.09) |
| Modelled fine dust emission | ||||
| Weighted fine dust emission from farms within 500 m median+ | 0.03 | 0.01 | 1.13 (1.08–1.17) | 1.14 (1.09–1.20) |
| Weighted fine dust emission from farms within 1000 m median+ | 1.30 | 1.10 | 1.10 (1.08–1.13) | 1.12 (1.09–1.15) |
| EMRs | ||||
| Subjects included with complete EMR data n | 11 868 | 10 532 | ||
| Asthma (ICPC R96) | 6.8 | 6.6 | 1.03 (0.93–1.15) | 1.06 (0.95–1.18) |
| COPD (ICPC R95 or R91) | 3.4 | 2.7 | 1.30 (1.11–1.52) | 0.81 (0.69–0.96) |
| Allergic rhinitis (ICPC R97) | 6.3 | 5.8 | 1.08 (0.97–1.21) | 1.28 (1.14–1.44) |
Data are presented as mean±sd or %, unless otherwise stated. OR (95% CI) were adjusted for age and sex. The likelihood of being a responder is modelled for different characteristics with logistic regression The presence of farm animals was also adjusted for the presence of other types of farm animals. Bold type indicates statistical significance (p<0.05). ICPC: International Classification of Primary Care; COPD: chronic obstructive pulmonary disease. #: OR (95% CI) for an increase per 10 years; ¶: OR (95% CI) for an increase per 100 m; +: OR (95% CI) for an interquartile range (IQR) increase in log-transformed exposure. IQR for ln (fine dust) for farms within 500 m 7.54 g·year−1·m−2, corresponding to a 1881-fold increase (exposure 7.54) for nontransformed values and IQR for ln (fine dust) for farms within 1000 m 3.08 g·year−1·m−2, corresponding to a 22-fold increase for nontransformed values.