Table 1. Demographic characteristics of lung cancer cases and controls in Xuanwei, China.

	Cases (n=260)		Controls (n=260)
Characteristic	n	%	n	%	P-value*
Ever Had Mining Job
Yes	48	18.46%	24	9.2%	<0.0001
No	212	81.54%	236	90.8%
Family History Lung
Cancer
Yes	22	8.46%	1	0.4%	<0.0001
No	238	91.54%	259	99.6%
Literate
Yes	136	52.31%	111	42.7%	0.025
No	123	47.31%	149	57.3%
History of non-malignant Lun g Disease
Yes	63	24.23%	11	4.23%	<0.0001
No	197	75.77%	249	95.77%
Ever Used Smoky Coal
Yes	249	95.77%	209	80.38%	<0.0001
No	11	4.23%	51	19.62%
Ever Smoked
Yes	234	88.85%	226	86.54%	0.64
No	26	11.15%	34	13.46%
	Mean	SD	Mean	SD	P-value*
Subject Age	53.17	12.48	52.64	12.57	0.62
Cigarettes Per Day	8.71	10.18	5.46	8.23	0.079
Pipe Per Day (34g)	13.79	12.78	18.84	13.78	<0.0001
Years of Smoking	30.21	15.48	27.75	16.26	0.079
Passive Smoke (Cigs/Day)	3.04	9.15	2.03	6.59	0.009
Annual Smoky Coal	3.8	2.35	3.45	2.51	0.077
Smoky Coal Years	47.42	16.68	38.33	23.42	<0.0001

^*P-values calculated by Wald chi-square test for categorical variables, t-test for continuous variables