Table 3. Effect of Cigarette Smoking and Risk of Lung Cancer by Smoky Coal Mine Source^&.

	Cases		Controls		OR (95% CI)*	P-value	OR (95% CI)*	P-value
Coal Mine Source	Smoker	Non-Smoker	Smoker	Non-Smoker	Cigarettes/Day		Cigarette Duration (Years)
Ever Used Smoky Coal (SC)	225	24	184	25	1.03 (1.00-1.05)	0.087	1.02 (0.99-1.04)	0.14
Lai Bin/Long Tan Only (LB/LT)	148	13	51	8	1.00 (0.96-1.05)	0.95	1.02 (0.99-1.06)	0.23
Mixed Lai Bin/Long Tan & Other Smoky Coal (MC)	15	3	3	1	-	-	-	-
Never Used Lai Bin/Long Tan Coal (No LB/LT)	62	8	130	16	1.07 (1.02-1.13)	0.029	1.03 (1.00-1.07)	0.071
Never Used Smoky Coal (No SC)	9	2	42	9	1.27 (0.77-2.09)	0.35	1.03 (0.98-1.08)	0.28
P-interaction (LB/LT; No LB/LT)						0.014		0.39
P-interaction (LB/LT; NSC)						0.01		0.17
P-interaction (SC; NSC)						0.0079		0.16
P-interaction (LB/LT; MC; No LB/LT; No SC)						0.074		0.61

^&Results presented as continuous variables

^*Adjusted for age, passive smoking, first-degree relative with lung cancer, literacy, ever had coal mining job, quantity of coal used