Table 5

Comparison of respiratory symptoms and lung function tests measured in the initial phase between participants and non-participants in the final phase

Hairdressing apprenticesOffice apprentices
Participants n=191Drop outs n=106p valueParticipants n=189Drop outs n=59p value
*Atopy defined by medical history of asthma or allergic rhinitis or medical history of atopic dermatitis.
†MHR: mucosal hyperresponsiveness, defined in this study as the presence of one or more of the following symptoms: fit of coughing, sneezing or runny nose, eye symptoms, and acute dyspnoea.
‡Percentage of the reference values established by Knudson and colleagues.8
§Methacholine dose-response slope, defined by the percent decline in FEV1 divided by the final cumulative dose of methacholine administered.
Gender (% females)88.578.10.0291.078.00.007
Age (y), mean (SD)17.0 (1.0)17.4 (1.7)0.00616.7 (1.0)17.0 (0.8)0.05
Smoking habits
    Non-smoker (%)50.834.00.00563.559.30.56
    Current or ex-smoker (%)49.266.032.340.7
    Cig/day, mean (SD)8.8 (6.4)10.4 (6.8)0.087.6 (4.9)12.8 (7.3)0.0002
Atopy* (%)16.227.40.0222.232.20.12
Symptoms
    Morning cough (%)2.13.80.394.811.90.05
    Cough day/night (%)2.14.70.2110.617.00.19
    Morning sputum (%)0.50.90.673.26.80.22
    Wheezing (%)5.814.20.0116.928.80.05
    Dyspnoea with wheezing (%)5.811.30.0911.117.00.24
    MHR† (%)24.127.40.5341.347.50.40
    Work related MHR1.11.90.553.23.40.93
Lung function tests‡(n=119)(n=120)(n=76)(n=48)
    % FVC, mean (SD)104.4 (10.8)100.9 (12.5)0.02100.3 (14.2)101.4 (14.0)0.67
    % FEV1, mean (SD)105.1 (10.6)101.1 (12.4)0.008100.3 (12.6)99.5 (13.5)0.72
    FEV1/FVC, mean (SD)89.7 (5.4)88.9 (5.8)0.2689.3 (5.9)87.3 (5.1)0.04
    %FEF25–75%, mean (SD)102.5 (20.7)98.6 (21.2)0.1697.8 (21.2)92.6 (18.1)0.16
Methacholine challenge
BHR (15% decrease in FEV1) (%)33.133.80.9231.931.80.99
log(methacholine slope§ + 0.02), mean (SD)−1.53 (0.22)−1.50 (0.24)0.35−1.50 (0.29)−1.51 (0.20)0.81