TABLE 1.

CLINICAL AND DEMOGRAPHIC CHARACTERISTICS OF STUDY PARTICIPANTS

	Non-COPD (n = 26)	GOLD 1–2 (n = 18)	GOLD 3–4 (n = 21)
Age, mean yr (IQR)	59 (57–64)	62 (58–63)	59 (57–63)
Sex, no. of males/females	14/12	9/9	15/6
Smokers, no. of former/current smokers	11/15	8/10	10/11
Pack-years, mean (IQR)	32 (12–44)	45 (35–58)	41 (38–50)
FEV1, mean (IQR)	2.9 (2.5–3.3)	2.1 (1.8–2.7)	0.6 (0.4–0.7)
FEV1:FVC, mean % (IQR)	79 (76–82)	63 (58–69)	27 (23–40)

Definition of abbreviations: COPD = chronic obstructive pulmonary disease; GOLD = Global Initiative for Chronic Obstructive Lung Disease; IQR = interquartile range.