Table 2.

Active and passive smoking and risk of lung cancer

	Case		Control		Cryde OR (95%CI)	Adjusted OR (95%CI)1
	N	%	N	%
Female
Active smoking
No	164	83.3	218	94.0	1	1
Yes	33	16.8	14	6.0	3.13 (1.62, 6.04)	2.52 (1.26, 5.03)
Total	197		232
Pack-years
Non smokers	164	83.3	218	94.0	1	1
<20	18	9.1	11	4.7	2.18 (1.00, 4.73)	1.78 (0.80, 3.97)
≥20	15	7.6	3	1.3	6.65 (1.89, 23.33)	5.42 (1.48, 19.87)
Total	197		232
P trend					0.0004	0.0040
Female non-smokers
Passive smoking at working place2
No exposure	115	70.1	167	76.6	1	1
Light	30	18.3	41	18.8	1.06 (0.63, 1.80)	1.35 (0.77, 2.34)
Heavy	19	11.6	10	4.6	2.76 (1.24, 6.12)	3.65 (1.57, 8.48)
Total	164		218
P trend					0.0349	0.0033
Passive smoking at home2
No exposure	57	35.2	84	38.5	1	1
Light	67	41.3	89	41.2	1.11(0.70, 1.76)	1.21(0.75,1.96)
Heavy	38	23.5	43	19.9	1.30(0.76, 2.26)	1.25(0.71, 2.20)
Total	162		216
P trend					0.3523	0.4030
Passive smoking at working place or home2
No exposure	38	23.8	67	30.7	1	1
Light	71	43.6	99	45.8	1.26 (0.77, 2.09)	1.41 (0.84,2.39)
Heavy	54	33.1	50	23.2	1.90 (1.10, 3.31)	1.98 (1.12,3.51)
Total	164		218
P trend					0.0223	0.0188
Male
Active smoking
No	15	7.4	67	28.6	1	1
Yes	187	92.6	167	71.4	5.00(2.75,9.09)	5.12(2.80,9.36)
Total	202		234
Pack-years
Non smokers	15	7.4	67	28.6	1	1
<20	21	10.4	51	21.8	1.84 (0.86,3.92)	1.97(0.91,4.25)
≥20	166	82.2	116	49.6	6.39 (3.48,11.74)	6.35 (3.44,11.71)
Total	202		234
P trend					<.0001	<.0001
Male non-smokers
Passive smoking at working place2
No exposure	4	26.7	31	46.3	1	1
Light	8	53.3	22	32.8	2.82 (0.75,10.54)	2.11 (0.51,8.76)
Heavy	3	20.0	14	20.9	1.66 (0.33,8.43)	1.76 (0.29,10.74)
Total	15		67
P trend					0.3947	0.4417
Passive smoking at home2
No exposure	14	93.3	46	68.7	1	1
Light	1	6.7	21	31.3	0.16 (0.02,1.27)	0.21 (0.02,1.76)
Total	15		67
Passive smoking at working place or home2
No exposure	4	26.7	24	35.8	1	1
Light	8	53.3	29	47.8	1.66 (0.44,6.17)	1.16 (0.28,4.89)
Heavy	3	20.0	14	16.4	1.29 (0.25,6.60)	1.26 (0.20,7.89)
Total	15		67
P trend					0.6912	0.7934

¹Odds Ratios were adjusted for age, education level and annual personal income.

²Only among nonsmokers;