Table 1.

Baseline characteristics of study population

Demographics	Total	Male				Female				P values (male vs. female)
		Total	COPD	Non-COPD	P value (COPD vs. non-COPD in male)	Total	COPD	Non-COPD	P value (COPD vs. non-COPD in female)
Number	130	60	45	15		70	47	23
Age, mean ± SD	64.17 ± 7.24	63.64 ± 5.19	63.20 ± 4.42	64.97 ± 7.06	0.374	64.63 ± 8.64	64.91 ± 8.05	64.04 ± 9.90	0.713	0.426
COPD, number (%)	92 (70.8%)	45 (75%)				47 (67.1%)				0.430
Smoking status
Pack-years	56.19 ± 28.75	66.32 ± 29.78	73.49 ± 27.89	44.80 ± 25.10	9.32E-04	47.51 ± 24.93	57.11 ± 23.27	27.89 ± 14.77	2.39E-08	1.82E-04
Years since quitting smoking	8.85 ± 8.84	8.30 ± 8.68	7.00 ± 6.68	12.2 ± 12.47	0.142	9.33 ± 9.00	5.96 ± 5.69	16.22 ± 10.62	1.64E-04	0.509
Spirometry
FEV1 (%predicted)	47.33 ± 34.55	43.20 ± 34.00	24.64 ± 9.16	98.87 ± 13.42	5.64E-14	50.87 ± 34.88	27.55 ± 9.70	98.52 ± 9.13	< 2.2E-16	0.207
FVC (%predicted)	75.98 ± 21.76	76.37 ± 20.19	68.26 ± 14.56	97.47 ± 17.55	9.41E-06	75.65 ± 23.18	62.20 ± 16.86	99.04 ± 10.45	1.35E-15	0.858
FEV1/FVC	0.46 ± 0.23	0.41 ± 0.23	0.29 ± 0.09	0.78 ± 0.05	< 2.2E-16	0.50 ± 0.23	0.36 ± 0.12	0.79 ± 0.05	< 2.2E-16	0.033

Abbreviations: COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity