Table 2

Demographic characteristic of patients

	Control (C)	Smoker (S)	COPD	p value†	C v S*	C v COPD*	S v COPD*
Results are expressed as median with 25–75th percentiles in parentheses.
FEV₁=forced expiratory volume in 1 second.
*p value for non-parametric Bonferroni Dunn’s post hoc test.
†p value for non-parametric Kruskal-Wallis test comparing the differences between the groups.
n	14	8	10	NS
Sex (M/F)	9/5	6/2	6/4
Age (years)*	50 (40–70)	41 (33–59)	63 (56–71)	NS	NS	NS	NS
Smoke (% of current smokers)	0%	100%	70%
Packs/year*	0	40 (32–45)	37.5 (32.5–52)				NS
FEV₁ (%)*	105 (100–110)	93 (90–103)	54 (50–62.5)	0.0001	p=0.009	p<0.0001	p<0.0001