Table 1 Characteristics of subjects with bronchial challenge at baseline according to whether they participated in both surveys or only in the first one.
| SAPALDIA 1 & 2 (n = 5825) | SAPALDIA 1 only (n = 1301) | p value | |
|---|---|---|---|
| Women (% ) | 50.3 | 45.5 | 0.002 |
| Mean (SD) height (cm) | 169 (9) | 169 (9) | 0.14 |
| Mean (SD) weight (kg) | 69 (13) | 69 (14) | 0.12 |
| Mean (SD) FEV1 (l/s) | 3.6 (0.8) | 3.6 (0.8) | 0.378 |
| Mean (SD) FVC (l) | 4.6 (1.0) | 4.5 (1.0) | 0.284 |
| Atopic (%) | 23.5 | 23.2 | 0.794 |
| FEV1/FVC ⩾0.70 (%) | 92.4 | 90.8 | 0.066 |
| Bronchial hyperresponsiveness (%) | 16.7 | 16.8 | 0.928 |
| Geometric mean methacholine dose‐response slope* | 1.1 | 1.1 | 0.860 |
| Severe respiratory infection as an infant (%) | 7.5 | 6.1 | 0.081 |
| No professional education (%) | 13.3 | 22.0 | <0.001 |
| Exposed to dust and fumes at work (%) | 31.1 | 36.2 | <0.001 |
| Mother smoked (%) | 12.5 | 15.1 | 0.012 |
| Father smoked (%) | 53.9 | 56.5 | 0.085 |
| Current smokers (%) | 31.8 | 40.6 | <0.001 |
| Geometric mean pack‐years in current smokers | 11.2 | 12.8 | 0.071 |
| Never smokers (%) | 45.5 | 36.3 | <0.001 |
| Physician‐diagnosed asthma (%) | 5.5 | 6.9 | 0.050 |
| Wheeze in last 12 months without cold (%) | 6.1 | 8.8 | 0.001 |
| Shortness of breath while walking (%) | 21.8 | 27.7 | <0.001 |
| Chronic cough (%) | 4.1 | 6.0 | 0.002 |
| Chronic phlegm (%) | 5.6 | 8.6 | <0.001 |
*Percentage decrease in FEV1 from its maximum level per µmol methacholine.