TABLE 1.

DEMOGRAPHIC AND CLINICAL CHARACTERISTICS OF SUBJECTS WITH SEVERE, EARLY-ONSET CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) AND OLDER SUBJECTS WITH SEVERE COPD: THE COPDGENE STUDY

	Subjects with Early-onset COPD	Older Subjects with COPD
	(n = 70)	(n = 306)	P Value
Age, yr*	51 ± 3	71 ± 4	<0.0001
Age at smoking initiation, yr*	16 ± 4	17 ± 5	0.003
Sex, % female	66	43	0.0004
Race
White, %	64	89
African American, %	36	11	<0.0001
Maternal COPD, %	23	12	0.03
Maternal smoking, %	70	44	0.0001
Maternal lung cancer, %	13	4	0.02
Paternal COPD, %	21	13	0.2
Paternal smoking, %	78	77	0.9
Pack-years of smoking*	42 ± 24	61 ± 30	<0.0001
FEV1 percent predicted*	34 ± 11	34 ± 10	0.9
BMI*	28 ± 9	27 ± 6	0.2
BODE Index score*	4.7 ± 1.5	4.6 ± 1.6	0.5
CT scan percent emphysema*	17 ± 14	23 ± 14	0.001
CT scan percent gas trapping*	48 ± 20	56 ± 16	0.003
Bronchodilator responsiveness, % FEV1*	9.0 ± 15	10 ± 14	0.7
Current smoking, %	56	17	<0.0001

Definition of abbreviations: BMI = body mass index; BODE = BMI, airflow obstruction, dyspnea, and exercise capacity; COPD = chronic obstructive pulmonary disease; CT = computed tomography.

^*Mean ± SD.