. Author manuscript; available in PMC: 2009 Aug 1.

Published in final edited form as: Cancer Epidemiol Biomarkers Prev. 2008 Aug;17(8):1974–1981. doi: 10.1158/1055-9965.EPI-08-0047

Table 4.

Involuntary smoking among never tobacco users and the risk of head and neck cancer, by cancer subsite

	Oral cavity				Pharynx				Larynx
	Ca	Co	OR^*	95 %CI	Ca	Co	OR^*^§	95 %CI	Ca	Co	OR^*	95 %CI
Ever IS exposure^§
never	53	794	1.00		72	794	1.00		23	794	1.00
ever at home or work	76	1078	0.93	( 0.61, 1.41)	135	1078	1.30	( 0.31, 5.34)	45	1078	1.71	( 0.98, 3.00)
Missing	2	67			1	67			0	16
P for heterogeneity			0.56				<.01				0.36
Duration of IS exposure at home²
never	46	1074	1.00		53	1074	1.00		36	938	1.00
1-15 years	12	294	1.58	( 0.73, 3.41)	27	294	1.88	( 0.42, 8.50)	8	278	1.44	( 0.59, 3.53)
>15 years	16	251	1.06	( 0.53, 2.11)	16	251	4.13	( 1.43,11.89)	15	221	2.58	( 1.20, 5.57)
Missing	4	143			5	143			3	68
P for trend			0.78				0.02				0.02
P for heterogeneity			0.23				0.24				0.77
Duration of IS exposure at work³
never	46	898	1.00		48	898	1.00		34	898	1.00
1-15 years	9	309	0.65	( 0.28, 1.51)	19	309	0.81	( 0.26, 2.50)	9	309	0.98	( 0.43, 2.23)
>15 years	10	185	1.31	( 0.57, 3.00)	13	185	5.16	( 0.28,95.95)	17	185	2.07	( 1.04, 4.11)
Missing	6	173			9	173			1	116
P for trend			0.75				0.37				0.07
P for heterogeneity			0.97				0.02				0.66

Adjusted for centers, age, sex, race/ethnicity, education and alcohol drinking (in drink-years).

^§

Estimates from random effect model.

Included Central Europe, Tampa, Latin America, Los Angeles, and Houston studies (no Tampa study for larynx).

Included Central Europe, Tampa, Puerto Rico, Latin America, and Los Angeles studies (no Tampa and Puerto Rico studies for larynx).

Included Central Europe, Tampa, Latin America, and Los Angeles studies (no Tampa study for larynx).