Table 1.

Demographic characteristics of study subjects

	Combined			Female			Male
	cases n=624	controls n=766	P	cases n=307	controls n=386	P	cases n=317	controls n=380	P
Sex, No. (%)			0.6582
Male	317(50.80)	380(49.61)
Female	307(49.20)	386(50.39)
Smoking Status, No. (%)			0.0576			0.0247			0.4502
Never	142(22.76)	136(17.75)		100(32.57)	90(23.32)		42(13.25)	46(12.11)
Former	264(42.31)	356(46.48)		104(33.88)	146(37.82)		160(50.47)	210(55.26)
Current	218(34.94)	274(35.77)		103(33.55)	150(38.86)		115(36.28)	124(32.63)
Mean age (SD)	61.8(11.6)	60.5(10.3)	0.0217	61.4(11.6)	59.6(10.8)	0.0248	62.2(11.6)	61.6(9.8)	0.2901
No. of cigarettes per day (SD)	21.3(16.6)	20.0(15.3)	0.1552	15.9(14.3)	16.6(14.0)	04538	26.6(17.0)	23.4(15.9)	0.0106
Years smoked (SD)	27.4(18.5)	25.4(16.8)	0.0269	23.5(19.5)	23.2(17.0)	0.9228	31.2(16.7)	27.5(16.4)	0.0040

P values were calculated with a X2 test for categorical variables and with a Wilcoxon test for continuous variables. All statistical tests were two-sided.

Never smokers were defined as those who had smoked fewer than 100 cigarettes in their lifetime.