Item content of variables tested for inclusion in the questionnaire
| Conceptual domain | Abbreviated item content |
| Dyspnoea | Shortness of breath when walking fast or walking up small slopes |
| Cough | Cough most days for a period of 3 months in a year |
| Cough most days for more than 2 years | |
| Phlegm | Phlegm most days for 3 months in a year |
| Phlegm most days for more than 2 years | |
| Wheezing | Wheezing sometime in the last year |
| Wheezing without a respiratory infection | |
| History of smoking | Current smoker? |
| Pack-years | |
| Have you smoked more than 100 cigarettes in your life? | |
| Previous respiratory disease | Previous diagnosis of asthma |
| Previous diagnosis of chronic bronchitis | |
| Previous diagnosis of emphysema | |
| Environment | Biomass smoke at home |
| Risk profession |