Table 1

Characteristics of the subjects excluded and included in the analyses*

P value
Female sex, n (%)1546 (50.7)2327 (49.3)0.25
Age, mean±SD (years)47.6±11.046.9±9.90.003
Body mass index, mean±SD (kg/m2)25.6±4.425.3±4.00.006
Low education, n (%)302 (9.9)269 (5.7)<0.001
Smoking habits, n (%)<0.001
Non-smoker1298 (42.7)2186 (46.6)
Ex-smoker855 (28.1)1461 (31.1)
Current smoker887 (29.2)1049 (22.3)
Second-hand smoking, n (%)955 (31.4)1313 (27.9)0.001
Past/current occupational exposure to vapours, gas, dusts or fumes, n (%)1343 (44.5)1947 (41.8)0.020
Ever asthma, n (%)291 (9.6)368 (7.8)0.007
High total serum IgE
(>100 kU/L), n (%)
577 (20.5)850 (18.9)0.107
Allergen sensitisation‡, n (%)722 (24.8)1160 (25.2)0.70
FEV1, mean±SD (L)3.41±0.833.51±0.79<0.001
%FEV1/FVC, mean±SD79.3±6.079.0±5.80.043
Slope, median (Q1–Q3) (% per µmol)1.0 (0.6–1.7)0.9 (0.5–1.6)<0.001
  • *All characteristics were measured at the second examination except for the slope (assessed at the first examination); subjects were excluded from the analyses either if they did not participate in the third examination (n=2010) or if they had no prebronchodilator lung function data available (n=1040). Percentages were calculated on subjects with data available for each variable.

  • †Obtained using Pearson’s χ2 test (categorical variables), Kruskal-Wallis rank test (slope) or ANOVA (the remaining variables).

  • ‡In the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults, specific IgE were only measured for subjects with a positive (>0.35 kU/L) Phadiatop Test (Phadia, Uppsala, Sweden); subjects with a negative test were assigned to the group with no sensitisation.