Table 2

Symptom frequency (%) and lung function on days with and without heating

Days UFGH used (n=1713 days)Days other heater used (n=2421 days)Days no heating used (n=1388 days)
Symptoms*
 Wheeze13.4 (2.2–37.5)10.4 (0.0–43.2)0.5 (0.0–27.1)
 Cough0.0 (0.0–3.4)0.0 (0.0–3.2)0.0 (0.0–1.6)
 Dyspnoea0.0 (0.0–2.1)0.0 (0.0–4.2)0.0 (0.0–0.6)
Lung function†
 morning PEF (litres/min)310 (111)297 (100)296 (102)
 evening PEF (litres/min)313 (107)298 (95)305 (103)
 morning–evening change PEF (%)1.86 (5.73)2.36 (6.55)3.66 (6.25)
 morning FEV1 (litres)1.90 (0.57)1.83 (0.60)1.86 (0.58)
 evening FEV1 (litres)1.90 (0.55)1.82 (0.59)1.86 (0.59)
 morning–evening change FEV1 (%)0.63 (5.53)0.67 (8.26)2.44 (6.32)

  • ↵* Median (IQR).

  • ↵† Mean (SD).

  • UFGH, unflued gas heater; FEV1, forced expiratory volume in 1 s; PEF, peak expiratory flow.