Alcohol consumption, cigarette smoking and the risk of subtypes of head-neck cancer: results from the Netherlands Cohort Study

Table 4 Combinations of categories of alcohol consumption and cigarette smoking and risk (multivariable ^a adjusted incidence RRs) of subtypes of head-neck cancer; Netherlands Cohort Study (NLCS), 1986 - 2003

	Head-neck cancer cases
	Overall					Subtypes
						OCC^b		OHPC^b		LC^b
	Alcohol consumption (grams ethanol/day)					Alcohol consumption^c		Alcohol consumption^c		Alcohol consumption^c
	0	>0 to <5	5 to <15	15 to <30	≥30	0-15	>15	0-15	>15	0-15	>15
Frequency of cigarette smoking ( N /day)
Never smokers
Cases/person time at risk^d	10/8959	13/9729	7/4245	11/1499	3/619	21/22933	8/2118	3/22933	3/2118	6/22933	3/2118
RR	1 (ref)	1.20	1.23	5.53	2.97	1 (ref)	4.16	1 (ref)	10.18	1 (ref)	3.05
95% CI		0.52 – 2.75	0.46 – 3.29	2.27 – 13.49	0.78 – 11.40		1.82 – 9.52		2.03 – 51.06		0.72 – 12.92
>0 to <20
Cases/person time at risk	21/4194	25/6534	37/7061	40/4814	32/2184	20/17789	18/6998	18/17789	12/6998	44/17789	41/6998
RR	1.89	1.56	2.04	2.63	3.81	0.76	1.55	4.02	5.63	2.66	4.19
95% CI	0.83 – 4.34	0.71 – 3.41	0.95 – 4.40	1.22 – 5.67	1.71 – 8.51	0.34 – 1.71	0.66 – 3.62	1.07 – 15.14	1.44 – 22.00	1.03 – 6.86	1.60 – 11.02
≥20
Cases/person time at risk	18/2102	29/2745	28/3162	41/3648	80/2856	7/8010	36/6504	16/8010	31/6504	52/8010	53/6504
RR	2.78	3.88	2.85	3.32	8.28	0.58	3.54	7.26	16.12	5.42	5.54
95% CI	1.18 – 6.54	1.77 – 8.49	1.28 – 6.34	1.52 – 7.25	3.98 – 17.22	0.21 – 1.58	1.66 – 7.52	1.86 – 28.44	4.31 – 60.27	2.10 – 13.98	2.15 – 14.27
P for interaction^e					0.03		0.10		0.09		0.19

^aAdjusted for age, sex, current cigarette smoking, and duration of cigarette smoking (years; continuous; centered).
^bOCC: oral cavity cancer; OHPC: oro-/hypopharyngeal cancer; LC: laryngeal cancer.
^cFor the categorical interaction analyses in HNC-subtypes, it was necessary to aggregate categories of alcohol consumption (grams ethanol/day) in order to obtain sufficient numbers in strata.
^dPerson time at risk in years.
^e P Value for interaction between categories of alcohol consumption and cigarette smoking, based on cross-product terms in the Cox proportional hazards model and Wald test.

ISSN: 1471-2407