Table 1.

Characteristics of COPD subjects and smoking-related phenotypes studied

			Cohort
			NETT n=362^*	Norway n=851^*	ECLIPSE n=1,734^*	COPDGene n=494^*
Characteristics	Males^*	N (%)	234 (64.6)	511 (60.0)	1,160 (66.9)	242 (49.0)
	Age in years^*	Mean (SD)	67.4 (5.8)	65.5 (10.1)	63.7 (7.1)	64.7 (8.1)
	Pack-years smoked^*	Mean (SD)	66.1 (30.9)	32.1 (18.6)	50.4 (27.4)	54.8 (26.8)
	Post-bronchodilator FEV₁ (% pred.)^*	Mean (SD)	29.1 (7.8)	50.7 (17.5)	44.8 (14.7)	48.7 (18.4)
	Post-bronchodilator FEV₁/FVC^*	Mean (SD)	0.32 (0.06)	0.51 (0.13)	0.45 (0.12)	0.48 (0.13)
	Enrollment	Years(s)	1998–2002	2003–2005	2005–2007	2008–2009
	Genotyping technology	Chip	Illumina Quad 610	Illumina HumanHap 550 V1, V3, and Duo	Illumina HumanHap 550 V3	Illumina Human Omni1-Quad
Phenotype studied	Age at smoking initiation	Mean (SD)	16.6 (3.6)	18.7 (5.1)	16.9 (4.4)	16.8 (4.4)
		Number of subjects with non-missing phenotype	362	851	1,690	494
		Lambda inflation factor	0.986	0.989	1.019	0.997
	Lifetime average CPD	Mean (SD)	32.4 (13.5)	15.7 (7.8)	25.5 (12.4)	27.6 (11.8)
		Number of subjects with non-missing phenotype	361	851	1,734	494
		Lambda inflation factor	1.002	0.996	1.018	0.996
	Smoking cessation	Current smokers, n (%)	0 (0)	404 (47.5)	610 (35.3)	150 (30.6)
		Former Smokers, n (%)	362 (100)	447 (52.5)	1120 (64.7)	340 (69.4)
		Lambda inflation factor	-	1.000	0.998	0.995
	Current CPD^†	Mean (SD)	-	13.1 (6.9)	15.6 (10.8)	18.4 (12.4)
		Number of subjects with non-missing phenotype	-	398	565	150
		Lambda inflation factor	-	0.995	1.005	0.997

calculated for subjects with at least 1 non-missing phenotype

^†

for subjects with reported current number of cigarettes smoked per day > 0

SD=Standard Deviation; FEV₁=Forced Expiratory Volume in 1 second; FVC=Forced Vital Capacity; CPD=number of cigarettes smoked per ^day