Total (n = 296) | No symptoms (n = 251) | Had symptoms at work (n = 45) | OR (95% CI) | |
Age mean (SD) years | 18.7 (3.1) | 18.6 (3.1) | 19.1 (3.6) | 1.1 (1.0 to 1.2)** |
Male gender | 44 (14.9) | 37 (14.7) | 7 (15.6) | 1.1 (0.4 to 2.6) |
Smoker | 34 (11.5) | 29 (11.6) | 5 (11.1) | 1.0 (0.4 to 2.6) |
Symptoms indicative of asthma | 125 (42.2) | 96 (38.2) | 29 (64.4) | 2.9 (1.5 to 5.7)** |
Symptoms indicative of COPD | 27 (9.1) | 18 (7.2) | 9 (20.0) | 3.2 (1.4 to 7.8)** |
Allergic symptoms | 118 (39.9) | 81 (32.3) | 37 (82.2) | 9.7 (4.3 to 21.8)** |
Skin symptoms | 49 (16.6) | 42 (16.7) | 7 (15.6) | 0.9 (0.4 to 2.2) |
Positive SPT to common allergens | 100 (33.8) | 75 (29.9) | 25 (55.6) | 2.9 (1.5 to 5.6)** |
Measurable PC20 (⩽32 mg/ml) | 92 (31.1) | 70 (27.9) | 22 (48.9) | 2.5 (1.3 to 4.7)** |
Data presented as n (%) unless otherwise stated.
**Univariable p value<0.50.
95% CI, 95% confidence interval; COPD, chronic obstructive pulmonary diseases; OR, odds ratio; PC20, level of the methacholine concentration that caused a decrease in FEV1 of 20%; SPT, skin-prick test.