Table 3. Clinical characteristics of subjects.

	Young COPD (n=16)	Aged COPD (n=16)	P value
Age (years)	47.88 (3.05)	72.31 (2.33)	<0.0001
Gender (male/female)	9/7	11/5	0.72
BMI (kg/m2)	23.16 (2.05)	22.99 (2.50)	0.84
Non-smokers/smokers	8/8	5/11	0.47
FEV1 (% predicted)	94.58 (19.83)	70.83 (19.63)	0.0019
FEV1/FVC (%)	66.79 (2.67)	58.94 (8.11)	0.0009
GOLD Grading
I	12	5
II	4	8
III	0	3
IV	0	0

Data are expressed as mean (SD). P-values were calculated using chi-square test or Student’s t-test. COPD, chronic obstructive pulmonary disease; BMI, body mass index; FEV1, forced expiratory volume in one second; FVC, forced vital capacity.