Table 1—

Summary of characteristics of the lung cancer cases and control smokers before and after matching

Parameter	Unmatched cohorts		Matched cohorts		p-value^#
Parameter	Control smokers	Lung cancer	Control smokers	Lung cancer	p-value^#
Subjects n	654	446	301	301
Males %	57	53	53	53
Age yrs	59±10	69±10	64±9	65±9	0.23
Height cm	170±0.09	167±0.08	168±0.09	168±0.08	0.58
Weight kg	80±16	69±15	78±15	71±16	<0.001
Smoking history
Age started smoking yrs	18±4	17±4	18±4	18±4	0.62
Cigarettes·day⁻¹	17±9	20±10	20±7	19±9	0.33
Current smokers %	24	35	22	39	<0.001
Pack-yrs	35±20	41±25	38±18	38±18	0.93
Lung function
FEV₁ L	2.84±0.82	1.86±0.69	2.56±0.80	1.90±0.69	<0.001
FEV₁ % pred	97±18	73±23	96±20	71±23	<0.001
FEV₁/FVC %	81±9	64±13	80±10	64±13	<0.001
Prevalence of COPD %
GOLD 1+	10	60	15	65	<0.001
GOLD 2+	6	51	8	50	<0.001
GOLD 3+	1.2	14	1.3	15	<0.001
History of comorbidities %
Chronic bronchitis	5	18	6	16	<0.001
Asthma	12	12	11	13	0.45

Data are presented as mean±sd, unless otherwise stated. FEV₁: forced expiratory volume in 1 s; % pred: % predicted; FVC: forced vital capacity; COPD: chronic obstructive pulmonary disease; GOLD: Global Initiative for Chronic Obstructive Lung Disease. ^#: comparison for matched cohorts only.