Adam33 polymorphisms are associated with COPD and lung function in long-term tobacco smokers

Respiratory Research

Table 1 Characteristics of subjects with COPD, smokers with normal pulmonary function and the unclassified* group

	UNAFFECTED SMOKERS (ppFEV₁ ≥ 80 and FEV₁/FVC ratio(%) ≥ 70, n = 311)	COPD (ppFEV₁ < 75 and FEV₁/FVC (%) < 70, n = 287)	Unclassified* n = 281
	Mean, SD	Mean, SD	Mean, SD	p Value ^†
pack years	45.9, 24.7	58.6, 31.1	55.3, 28.3	<0.001
Age	64.4, 10.0	67.3, 8.0	66.1, 9.4	<0.001
FEV₁ (L/sec)	3.1, 0.5	1.7, 0.6	2.5, 0.53	<0.001
ppFEV₁	94.7, 10.1	53.5, 14.0	75.9, 12.9	<0.001
FEV₁/FVC (%)	78.3, 6.0	55.3, 10.8	52.4, 17.7	<0.001
ppFEF_25–75	85.5, 23.6	26.6, 13.4	71.1, 7.73	<0.001
% male	95.8	97.2	98.2	0.22

*Of 880 Caucasian who smoked ≥ 20 pack years and were older than 50 years, 281 fell into the group excluded from categorical analyses (FEV1/FVC ratio ≥ 70% and ppFEV₁ < 80% or FEV1/FVC ratio < 70% and ppFEV₁ ≥ 75%, unclassified). The analysis shows significant differences in age, and pack years smoked. ppFEV₁, FEV1/FVC ratio, and ppFEF_25–75 were different due to selection criteria.
† Chi-square for sex and ANOVA for the rest of the variables

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