Table 5– Demographic and clinical features of cases labelled by study participants as smoking-related interstitial lung disease (ILD), ILD in a smoker or other

	Smoking-related ILD	ILD in a smoker	Other	p-value
Subjects	8	13	79
Age years	47.00±5.00	54.64±10.93	54.98±11.82	0.211
Males/females/NA	4/3/1	5/8	42/34	0.520
Smoking history				0.103
Never	1	6	41
Former/current	7	7	38
Pack-years	34.17±29.90	17.83±22.69	13.73±28.19	0.215
Clinical history				0.642
Cough yes/no/NA	5/1/2	9/4/0	61/15/3
Cough duration months	16.2±11.14	31.00±41.53	24.80±35.88	0.737
Dyspnoea yes/no	8/0	13/0	72/7	0.368
Dyspnoea duration months	20.62±16.31	31.08±39.46	23.48±33.76	0.732
Pulmonary function
FVC % predicted	81.90±19.09	69.38±9.05	64.33±20.38	0.045
FEV₁ % predicted	79.75±18.28	77.38±10.94	69.90±20.15	0.202
FEV₁/FVC	74.50±9.93	93.50±14.50	94.33±17.17	0.02
TLC % predicted	91.17±10.98	74.92±10.59	68.9±16.67	0.0039
D_LCO % predicted	48.87±13.72	46.08±19.28	50.39±19.47	0.750

Data are presented as n or mean±sd, unless otherwise stated. NA: not available; FVC: forced vital capacity; FEV₁: forced expiratory volume in 1 s; TLC: total lung capacity; D_LCO: diffusing capacity of the lung for carbon monoxide.