Table 1.

Characteristics of the study population.

Characteristics	Non-smoker (n = 40)	Smoker (n = 50)	COPD (n = 50)	p value
Age, years	59.25 ± 4.00	58.64 ± 4.11	58.10 ± 4.45	0.438
Sex, male/female	27/13	39/11	42/8	0.177
BMI, kg/m2	21.70 ± 1.80	21.73 ± 1.70	21.28 ± 1.74	0.370
FEV1/FVC, %	87.53 ± 4.20	80.78 ± 5.68	56.84 ± 11.59	<0.001
FEV1, %	92.38 ± 5.12	87.68 ± 5.44	56.16 ± 15.95	<0.001
Smoking, pack-years	–	38.16 ± 11.27	41.08 ± 12.40	0.221

BMI, body mass index; COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in one second; FVC, forced vital capacity.