Baseline characteristics of patients
| Baseline characteristics | UFGH (n=33) | Other heating (n=38) | p Value |
| Demographics | |||
| Sex (F/M) | 18/15 | 23/15 | 0.641 |
| Age (years)* | 70.0 (64.0–71.0) | 67.5 (66.0–76.0) | 0.132 |
| Occupation (prof/semi/trades)† | 19/6/7 | 21/11/4 | 0.345 |
| Socioeconomic Index* ‡ | 83.0 (61.0–91.5) | 81.0 (67.5–94.0) | 0.867 |
| Baseline lung function measurements | |||
| % Pred FVC§ | 96.9 (21.7) | 98.5 (20.1) | 0.492 |
| % Pred FEV1§ | 76.0 (16.1) | 79.3 (25.9) | 0.467 |
| % FEV/FVC§ | 64.3 (10.0) | 64.0 (14.3) | 0.930 |
| % Pred PEF§ | 87.1 (22.3) | 90.7 (26.0) | 0.383 |
| Clinical parameters | |||
| Asthma severity (intermittent/persistent) | 17/15¶ | 18/20 | 0.301 |
| Daily inhaled corticoid steroid use | 28/33 (85%) | 34/38 (90%) | 0.912 |
| Ex-smokers | 17/33 (53.1%) | 15/37‡ (46.9%) | 0.253 |
| Age at asthma diagnosis (years)* | 23.0 (5.0–53.0) | 36.0 (13.5–55.0) | 0.316 |
| Seasonal asthma | 21/33 (65.7%) | 19/38 (50.0%) | 0.334 |
| Symptoms occurring primarily in winter | 16/32 (50%) | 13/35 (37.1%) | 0.164 |
↵* Median (IQR).
↵† Prof, professional; semi, semi-professional; trades, tradesperson.
↵‡ Index of socio-economic disadvantage based on residential address.
↵§ Mean (SD).
↵¶ Missing data point.
UFGH, unflued gas heater; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; PEF, peak expiratory flow; Pred, predicted.