Table 4 Relation between the asthma severity score and O3 within subgroups per each increase of 10 days of ozone (O3)-days
VariableNoOR (95 % CI)
All subjects2231.29 (1.16 to 1.45)
Sex
    Men1161.21 (1.04 to 1.40)
    Women1071.46 (1.22 to 1.76)
Age
    <45 years1391.34 (1.15 to 1.57)
    ⩾45 years841.23 (1.03 to 1.47)
Smoking habits
    Never smokers1011.35 (1.12 to 1.62)
    Ex-smokers801.30 (1.09 to 1.55)
    Current smokers421.12 (0.84 to 1.49)
Occupational exposure
    No1801.31 (1.16 to 1.48)
    Yes431.29 (0.94 to 1.77)
Education level
    Primary781.33 (1.07 to 1.66)
    Secondary571.39 (1.09 to 1.77)
    University881.23 (1.04 to 1.46)
Centre
    Paris420.98 (0.53 to 1.80)
    Lyon453.43 (1.82 to 6.47)
    Marseille381.26 (0.79 to 2.01)
    Montpellier161.22 (0.76 to 1.96)
    Grenoble820.98 (0.70 to 1.35)
6-month periods
    October-March1211.24 (1.08 to 1.43)
    April-September1021.48 (1.19 to 1.85)
  • OR given for one class difference in score and for an increase of 10 days of O3-days.

  • OR, odds ratio adjusted for age, sex, smoking habits, occupational exposure and educational level; 95% CI, 95% confidence interval.