Table 1. Comparison of female lung cancer cases and controls by sociodemographic characteristics and exposure to tobacco smoke, Gansu province, China, 1994-1998.

Characteristic	Cases1	Controls1	OR	95% CI	p value2
	(n=109)	(n=435)
Age, years
<45	21	51	1.0	Reference	0.245
45-54	38	162	0.57	0.31-1.07
55-64	34	144	0.58	0.30-1.09
65+	16	78	0.50	0.24-1.07
Prefecture
Qingyang	48	180	1.0	Reference	0.903
Pingliang	61	255	0.97	0.63-1.50
Education
Primary or less	95	415	1.0	Reference	0.019
Tech/vocation	14	18	3.0	1.40-6.49
College and above	0	2	NA
Income, yuan/year
< 2,000	21	106	1.0	Reference	0.107
2,000-2,999	15	86	0.96	0.46-2.01
3,000-4,399	32	110	1.7	0.88-3.15
4,400+	41	125	1.8	0.98-3.24
Number of color TVs
None	71	352	1.0	Reference	<0.001
At least one	38	81	2.5	1.53-3.94
Marital status
Married	94	371	1.0	Reference	0.814
Widowed	15	64	0.92	0.47-1.80
Smoking status
Never smoker	98	389	1.0	Reference	0.981
Ever smoker	11	45	1.0	0.50-2.05
Environmental tobacco smoke in childhood, pack-years
<1	30	153	1.0	Reference	0.149
1-9	41	159	1.3	0.76-2.17
10+	16	39	2.0	1.00-4.19

¹ Numbers may not add up to column totals because of missing data.

² Test of independence, adjusted for reference age and prefecture.

OR: odds ratio, CI: confidence interval.