Table 3.

Association of HNSCC with smokeless tobacco by cancer site.

Variables	Control	Larynx					Oral cavity					Pharynx
		Case	OR1	95%CI1	OR2	95%CI2	Case	OR1	95%CI1	OR2	95%CI2	Case	OR1	95%CI1	OR2	95%CI2
Smokeless tobacco use history
Never	1,200	166	1.00	---	1.00	---	378	1.00	---	1.00	---	445	1.00	---	1.00	---
≥ 20 times	22	3	0.98	0.29, 3.35	0.67	0.19, 2.36	8	1.26	0.55, 2.88	0.90	0.38, 2.12	21	2.09	1.13, 3.88	1.59	0.84, 3.01
Duration of smokeless tobacco use in lifetime (y)
Never	1,200	166	1.00	---	1.00	---	378	1.00	---	1.00	---	445	1.00	---	1.00	---
> 0 to < 2	10	0	---	---	---	---	2	0.75	0.16, 3.43	0.68	0.15, 3.19	4	0.95	0.29, 3.05	0.84	0.26, 2.74
≥ 2 to <10	19	0	---	---	---	---	6	1.15	0.45, 2.91	0.90	0.34, 2.35	12	1.41	0.67, 2.95	1.07	0.49, 2.32
≥ 10	4	3	5.48	1.20, 24.97	5.35	1.11, 25.68	4	3.41	0.84, 13.83	2.88	0.68, 12.25	9	4.81	1.46, 15.81	4.46	1.33, 14.93
p for trend			0.056		0.09			0.086		0.19		0.008			0.017
Average frequency of smokeless tobacco use per week (times)
Never	1,200	166	1.00	---	1.00	---	378	1.00	---	1.00	---	445	1.00	---	1.00	---
> 0 to < 7	19	1	0.38	0.05, 2.84	0.40	0.05, 3.07	4	0.75	0.25, 2.23	0.78	0.26, 2.36	11	1.33	0.62, 2.83	1.32	0.62, 2.84
≥ 7	12	2	1.20	0.26, 5.47	0.74	0.16, 3.47	4	1.17	0.37, 3.68	0.74	0.23, 2.42	15	2.66	1.23, 5.79	1.84	0.82, 4.13
p for trend			0.887		0.652			0.827		0.601			0.013		0.132
Lifetime numbers of smokeless tobacco use (times/wk*y)
Never	1,200	166	1.00	---	1.00	---	378	1.00	---	1.00	---	445	1.00	---	1.00	---
> 0 to < 20	16	1	0.45	0.06, 3.41	0.46	0.06, 3.65	1	0.23	0.03, 1.73	0.25	0.03, 1.90	10	1.42	0.64, 3.17	1.45	0.64, 3.26
≥ 20	11	2	1.32	0.29, 6.05	0.92	0.20, 4.33	7	2.25	0.86, 5.89	1.55	0.57, 4.21	15	2.91	1.31, 6.44	2.12	0.93, 4.84
p for trend			0.726		0.913			0.098		0.384			0.009		0.076

¹OR adjusted for age and gender.

²OR adjusted for age, gender, race (White, non-White), education (3 categories), smoking (continuous), ever smoker, alcohol drinking (continuous).