No respiratory symptoms | 1.0 | | 1.0 | | 1.0 | | 1.0 | |
Symptom group | | | | | | | | |
Cough symptoms | 4.0 | 2.4 to 6.5 | 6.2 | 3.1 to 12.3 | 1.5 | 0.9 to 2.4 | 1.2 | 0.8 to 1.8 |
Asthma-like symptoms | 4.7 | 2.9 to 7.7 | 7.8 | 4.0 to 15.0 | 1.2 | 0.7 to 2.1 | 1.3 | 0.8 to 1.8 |
Moderate dyspnoea | 4.5 | 2.5 to 8.3 | 5.1 | 2.3 to 11.3 | 1.2 | 0.5 to 2.7 | 0.8 | 0.4 to 1.3 |
Severe dyspnoea | 9.6 | 5.1 to 18.3 | 13.0 | 6.0 to 28.3 | 1.5 | 0.5 to 4.6 | 1.5 | 0.9 to 2.7 |
Symptom score | | | | | | | | |
1–3 | 2.3 | 1.4 to 4.0 | 3.4 | 1.7 to 6.8 | 1.5 | 1.0 to 2.4 | 0.9 | 0.6 to 1.3 |
4–6 | 4.1 | 2.3 to 7.5 | 9.6 | 4.5 to 20.8 | 1.5 | 0.7 to 3.2 | 1.1 | 0.6 to 1.9 |
⩾7 | 13.6 | 7.1 to 25.9 | 21.5 | 9.4 to 49.5 | 2.0 | 0.6 to 6.2 | 3.0 | 1.5 to 6.0 |
p trend for symptom score | <0.001 | <0.001 | 0.09 | 0.02 |