Table 4.

Association between smoking variables and histologic subtypes of lung cancer

	CONTROLS	ADENOCARCINOMA (1)		SQUAMOUS CELL CARCINOMA (2)		SMALL CELL CARCINOMA (3)		p-value for Homogeneity Test
	N = 757	N = 514	OR (95%CI)	N = 67	OR (95%CI)	N = 88	OR (95%CI)	(1)/(2)	(1)/(3)	(2)/(3)
SMOKING STATUS
Never smokers	341	129	Ref	7	Ref	3	Ref
Former smokers	246	149	1.76 (1.31; 2.37)	24	5.23 (2.17; 12.59)	15	7.66 (2.17; 27.10)	0.15	0.89	0.43
Current smokers	170	236	3.50 (2.61; 4.70)	36	12.56 (5.33; 29.58)	70	59.43 (18.11; 194.97)	0.01	<  0.001	0.01
INTENSITY
Per 10 cigarettes/day			2.04 (1.79; 2.31)		2.82 (2.23; 3.56)		3.45 (2.79; 4.28)	0.01	<  0.001	0.14
DURATION
Per 10 years			1.44 (1.35; 1.54)		2.04 (1.71; 2.43)		2.83 (2.26; 3.55)	<  0.001	<  0.001	0.02
PACK-YEARS
Per 10 pack-years			1.55 (1.45; 1.66)		1.86 (1.66; 2.09)		2.13 (1.90; 2.38)	<  0.001	<  0.001	0.04
TIME SINCE CESSATION (among ever smokers)
Per 1 year			0.96 (0.94; 0.97)		0.92 (0.89; 0.95)		0.87 (0.82; 0.91)	0.03	<  0.001	0.05
CSI
Per 1 CSI unit			2.54 (2.18; 2.96)		5.12 (3.61; 7.26)		9.98 (6.60; 15.09)	<  0.001	<  0.001	0.01

Abbreviations: CI confidence interval, CSI comprehensive smoking index, OR odds ratio

Odds ratio were adjusted for age (continuous), area of residence, education, and BMI 2 years before the interview (continuous)