Table 1. Comparison of demographic and other characteristics between cases and controls (n = 5744).

Variable		Cases (n = 2821)		Controls (n = 2923)		P*
		No.	%	No.	%
Sex	Male	1507	53.42	1448	49.54	0.003
	Female	1314	46.58	1475	50.46
Race	Black	389	13.79	383	13.10	0.028
	Hispanic	154	5.46	209	7.15
	White	2278	80.75	2331	79.74
Smoking status	Never	453	16.06	693	23.71	<0.0001
	Former	1225	43.42	1168	39.96
	Current	1143	40.52	1062	36.33
Emphysema	Yes	524	18.57	169	5.78	<0.0001
	No	2050	72.67	2571	87.98
Asthma	Yes	386	13.68	351	12.01	<0.0001
	No	2176	77.14	2407	82.35
Hay fever	Yes	421	14.92	621	21.25	<0.0001
	No	2127	75.40	2142	73.28
Family historya	Yes	1637	58.03	1545	52.86	<0.0001
	No	757	26.83	1062	36.33
Dust exposureb	Yes	818	29.00	662	22.65	<0.0001
	No	1569	55.62	1948	66.40
SHSc	Yes	1597	56.61	1746	59.73	<0.0001
	No	168	5.96	348	11.91
		No.	Mean(SD)	No.	Mean(SD)	p**
Age (year)		2821	62.49 (10.86)	2923	58.75 (11.47)	<0.0001
Addction index (0–10)d		2294	4.56 (2.41)	2200	4.00 (2.59)	<0.0001
Smoking pack-yeard		2329	49.80 (37.41)	2205	38.78 (29.92)	<0.0001
Time since smoking cessation(year)e		1214	14.86 (11.11)	1155	15.95 (11.89)	0.021
Calories (kcal/day)		2821	2204 (907)	2923	2206 (900)	0.936
Alcohol (g/day)		2821	8.24 (18.00)	2923	7.71 (17.88)	0.261

^aTotal 12.9% missing. ^b Total 13% missing. ^c Total 32.8% missing. ^d Smokers only. ^e Former smokers only.

^*p-value, two-sided chi-square test. ** p-value, Student’s t-test.