Table 2. Cigarette use and risk of ESCC in cases and controls in the two phases of the Golestan Case-Control Study of ESCC in Golestan Province, Iran.

	Hospital study				Neighborhood study				P for heterogeneity adjusted ORs
	ESCC%	Control%	CrudeOR (95% CI)	Adjusted*OR (95% CI)	ESCC%	Control%	CrudeOR (95% CI)	Adjusted*OR (95% CI)
Cigarette Smoking
Never	107(82)	226(87)	1.00	1.00	232(78)	471(83)	1.00	1.00
Ever	23(18)	34(13)	1.48 (0.80–2.75)	1.33(0.67–2.64)	67(22)	99(17)	1.35 (0.92–2.00)	1.05(0.67–1.64)	0.59
Average amount (cigarettes per day)
Never Used	107(82)	226(87)	1.00	1.00	232(78)	471(83)	1.00	1.00
< = Median**	10(8)	20(8)	1.09 (0.48–2.49)	1.04(0.42–2.61)	22(7)	49(9)	0.89 (0.51–1.56)	0.75(0.41–1.38)	0.56
>Median	13(10)	14(5)	2.06 (0.90–4.71)	1.71(0.68–4.27)	45(15)	50(9)	1.84 (1.13–2.99)	1.38(0.80–2.37)	0.70
Duration
Never Used	107(82)	226(87)	1.00	1.00	232(78)	471(83)	1.00	1.00
< = Median	16(12)	19(7)	1.96 (0.90–4.28)	1.64(0.72–3.69)	30(10)	49(9)	1.18 (0.72–1.94)	0.88(0.50–1.52)	0.29
>Median	7(6)	15(6)	0.99 (0.38–2.55)	0.94(0.33–2.62)	37(12)	50(9)	1.58 (0.95–2.62)	1.27(0.73–2.23)	0.58
Cumulative ***
Never Used	107(82)	226(87)	1.00	1.00	232(78)	471(83)	1.00	1.00
< = Median	10(8)	17(6.5)	1.30 (0.55–3.07)	1.22(0.47–3.19)	30(10)	49(9)	1.22 (0.74–2.01)	1.00(0.58–1.73)	0.73
>Median	13(10)	17(6.5)	1.66 (0.76–3.62)	1.42(0.59–3.40)	37(12)	50(9)	1.52 (0.91–2.53)	1.11(0.62–1.98)	0.66
Age Started
Never Used	107(82)	226(87)	1.00	1.00	232(78)	471(83)	1.00	1.00
>Median	10(8)	17(6.5)	1.26 (0.54–2.91)	1.01(0.41–2.48)	23(8)	49(9)	0.98 (0.57–1.68)	0.84(0.47–1.50)	.75
< = Median	13(10)	17(6.5)	1.76 (0.76–4.06)	1.75(0.72–4.25)	44(15)	50(9)	1.75 (1.08–2.84)	1.28(0.74–2.20)	.58

^*Adjusted for opium, nass, hookah, ethnicity, education and place of residence.

^**Median of control group in each set.

^***Cumulative = duration×amount.