Determinants of respiratory symptoms and BHR during methacholine challenge in the initial and final cross sectional phases and predictors of the incidence of respiratory symptoms of the longitudinal survey: logistic regression analyses*
| Morning cough OR (95% CI)§ | Day or night cough OR (95% CI) | Wheezing OR (95% CI) | Dyspnoea OR (95% CI) | MHR† OR (95% CI) | BHR‡ OR (95% CI) | |
|---|---|---|---|---|---|---|
| Initial phase: 297 hairdressing apprentices, 248 office apprentices; final phase: 280 hairdressing apprentices, 250 office apprentices; for BHR, 234 hairdressing apprentices and 116 office apprentices at the initial phase and 204 hairdressing apprentices and 129 office apprentices at the final phase. | ||||||
| Longitudinal survey: 191 hairdressing apprentices and 189 office apprentices; for BHR. | ||||||
| *Variables examined in the models are: group status (fixed variable), gender, age, smoking status, atopy. As age did not have any significant effect on any of the respiratory symptoms studied, it was removed from the table. Similarly, gender was removed from the table in the longitudinal survey. | ||||||
| –, variables not entered in the model. | ||||||
| †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. | ||||||
| ‡BHR: 15% fall in FEV1 during the methacholine challenge test. | ||||||
| §Adjusted odds ratio and 95% confidence interval. | ||||||
| ¶Atopy defined by positive medical history of asthma or allergic rhinitis or medical history of atopic dermatitis. Information on this parameter was missing for 89 hairdressing apprentices and 61 office apprentices participating only in the final phase. Therefore, this parameter was not examined in the logistic regression models of the final phase. | ||||||
| **Atopy not taken into account as no subject with atopy at the initial phase presented BHR at the final phase. | ||||||
| Initial phase | ||||||
| Hairdressing apprentices v office apprentices | 0.3 (0.1 to 0.8) | 0.2 (0.1 to 0.4) | 0.3 (0.2 to 0.6) | 0.5 (0.3 to 1.1) | 0.4 (0.3 to 0.6) | 1.1 (0.7 to 1.9) |
| Gender (female v male) | – | – | – | 0.4 (0.2 to 1.0) | – | 2.3 (1.1 to 4.8) |
| Current or ex-smokers v non-smokers | 9.3 (2.7 to 32.4) | 6.2 (2.7 to 14.3) | 2.0 (1.1 to 3.5) | 1.7 (1.1 to 2.5) | – | |
| Atopy¶ | 4.2 (1.8 to 10.1) | 3.9 (1.9 to 8.0) | 9.6 (5.5 to 16.7) | 34.4 (14.9 to 79.7) | 5.9 (3.7 to 9.3) | 2.3 (1.3 to 4.1) |
| Final phase | ||||||
| Hairdressing apprentices v office apprentices | 0.6 (0.2 to 1.4) | 0.3 (0.2 to 0.8) | 0.4 (0.2 to 0.6) | 0.5 (0.3 to 1.0) | 0.5 (0.4 to 0.8) | 1.6 (1.0 to 2.6) |
| Gender (female v male) | – | – | – | – | – | 3.6 (1.4 to 9.5) |
| Current or ex-smokers v non-smokers | 6.8 (1.9 to 23.8) | – | 2.6 (1.5 to 4.5) | – | 1.6 (1.1 to 2.4) | – |
| Longitudinal survey | ||||||
| Hairdressing apprentices v office apprentices | 0.7 (0.2 to 2.3) | 0.8 (0.3 to 2.4) | 0.8 (0.4 to 1.7) | 0.6 (0.2 to 1.6) | 0.9 (0.5 to 1.7) | 1.4 (0.5 to 3.9) |
| Current or ex-smokers v non-smokers | – | – | – | – | – | 3.0 (1.1 to 8.2) |
| Atopy¶ | – | 4.6 (1.6 to 13.4) | 7.0 (3.2 to 15.1) | 4.6 (1.7 to 12.6) | 2.6 (1.1 to 5.8) | ** |