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
*Percentage decrease in FEV1 from its maximum level per µmol methacholine.
Women (%)50.345.50.002
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 (%)23.523.20.794
FEV1/FVC ⩾0.70 (%)92.490.80.066
Bronchial hyperresponsiveness (%)16.716.80.928
Geometric mean methacholine dose-response slope*1.11.10.860
Severe respiratory infection as an infant (%)7.56.10.081
No professional education (%)13.322.0<0.001
Exposed to dust and fumes at work (%)31.136.2<0.001
Mother smoked (%)12.515.10.012
Father smoked (%)53.956.50.085
Current smokers (%)31.840.6<0.001
Geometric mean pack-years in current smokers11.212.80.071
Never smokers (%)45.536.3<0.001
Physician-diagnosed asthma (%)5.56.90.050
Wheeze in last 12 months without cold (%)6.18.80.001
Shortness of breath while walking (%)21.827.7<0.001
Chronic cough (%)4.16.00.002
Chronic phlegm (%)5.68.6<0.001