Table 1

Studies examining risk of COPD in α₁-antitrypsin PI MZ heterozygotes

Author	Year	Country	Source of cases	Source of controls	COPD definition	Cases PI MZ/PI MM	Controls PI MZ/PI MM	Adjustment for smoking
PI, protease inhibitor; COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; PEFR, peak expiratory flow rate; PFT, pulmonary function test; MMEF, maximum mid-expiratory flow; Tlco, carbon monoxide transfer factor.
(A) Case-control studies
Fagerhol¹⁸	1969	Norway	Hospital patients	Hospital patients with other chest diseases	Clinical diagnosis (emphysema, chronic bronchitis)	5/135	9/268	None
Talamo³¹	1972	USA	Hospital pulmonary clinic	Healthy prison inmates, employees	FEV₁/FVC <0.72, >PEFR <80% predicted	4/84	3/94	None
Kueppers²⁴	1974	Germany	Retired workers, hospital inpatients	Blood donors	Combination of PFTs and blood gases	12/138	1/193	None
Barnett¹⁷	1975	USA	Patients seen at the University of North Carolina	Patients with non-pulmonary diseases, patients’ spouses, >hospital employees	MMEF <50% >predicted	10/87	2/81	None
Cox¹⁴	1976	Canada	Hospital pulmonary clinic, hospital inpatients	Healthy hospital employees, school children	Clinical diagnosis (bronchitis), Tlco <80% predicted (emphysema)	6/101	14/644	None
Kueppers²⁵	1977	USA	Hospital pulmonary clinic, local physicians	Hospital patients with fractures or dental extractions	FEV₁ <70% predicted	9/97	6/98	Matched on smoking status
Abboud¹²	1979	Canada	Hospital pulmonary clinic	Healthy hospital staff, patients’ spouses	FEV₁/FVC <0.50	5/42	0/26	None
Bartmann¹³	1985	Germany	Rehabilitation clinic	Blood donors, hospital employees	Clinical diagnosis, including PFTs and x ray	31/429	8/583	None
Lieberman²⁶	1986	USA	Patients undergoing carotid body surgery	Junior high school students	Clinical diagnosis	57/595	34/1213	None
Poller²⁹	1990	Germany	Hospital clinic	Patients without pulmonary disease or family history	Clinical diagnosis, plethysmography	16/137	7/130	None
Sandford³⁰	1999	Canada	Patients undergoing lobar or lung resection	Patients undergoing lobar or lung resection	FEV₁ <80% predicted, FEV₁/FVC <0.7	12/163	0/66	Logistic regression
(B) Cross sectional studies
Author	Year	Country	Study population	COPD diagnosis		No. COPD/total PI MZ	No. COPD/total PI MM	Adjustment for smoking
Klayton²³	1975	USA	Random selection of employees in research facilities, age >40	FEV₁ <2 SD below predicted		13/27	69/262	Stratified by smoking status
Matzen²⁷	1977	USA	Clinic patients without previous diagnosis of pulmonary disease	Clinical diagnosis		2/12	27/427	None
Chan-Yeung¹¹	1978	Canada	Caucasian employees of sawmills and grain elevator terminals	FEV₁ <80% predicted, >FEV₁/FVC <0.7		0/31	98/1006	Stratified by smoking status
Gulsvik²⁰	1979	Norway	Community survey, ages 15-70, oversampled those with symptoms	Clinical diagnosis, including PFTs and chest x ray		7/51	123/1054	None
Dahl¹⁵	2002	Denmark	Randomly selected adults from Danish general population	FEV₁ <80% predicted, >FEV₁/FVC <0.7		86/450	1053/7018	Logistic regression