Table 1.

Characteristics of COPD patients and healthy volunteers (control group)

	Patients with COPD (n=113)	Control group (n=44)
Male/female (n)	78/35	27/17
Age (years; mean ± SD)	66±8	61±9
Smoking status (n) current/former/nonsmoker	40/70/3	13/11/20
GOLD obstruction stage
Mild (n/%)	4/3.54	N/A
Moderate (n/%)	22/19.47	N/A
Severe (n/%)	43/38.06	N/A
Very severe (n/%)	44/38.93	N/A

Abbreviations: SD, standard deviation; GOLD, Global Initiative for Chronic Obstructive Lung Disease; NA, not available.