Alcohol drinking in never users of tobacco, cigarette smoking in never drinkers, and the risk of head and neck cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium.
BACKGROUND
At least 75% of head and neck cancers are attributable to a combination of cigarette smoking and alcohol drinking. A precise understanding of the independent association of each of these factors in the absence of the other with the risk of head and neck cancer is needed to elucidate mechanisms of head and neck carcinogenesis and to assess the efficacy of interventions aimed at controlling either risk factor.


METHODS
We examined the extent to which head and neck cancer is associated with cigarette smoking among never drinkers and with alcohol drinking among never users of tobacco. We pooled individual-level data from 15 case-control studies that included 10,244 head and neck cancer case subjects and 15,227 control subjects, of whom 1072 case subjects and 5775 control subjects were never users of tobacco and 1598 case subjects and 4051 control subjects were never drinkers of alcohol. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression models. All statistical tests were two-sided.


RESULTS
Among never drinkers, cigarette smoking was associated with an increased risk of head and neck cancer (OR for ever versus never smoking = 2.13, 95% CI = 1.52 to 2.98), and there were clear dose-response relationships for the frequency, duration, and number of pack-years of cigarette smoking. Approximately 24% (95% CI = 16% to 31%) of head and neck cancer cases among nondrinkers in this study would have been prevented if these individuals had not smoked cigarettes. Among never users of tobacco, alcohol consumption was associated with an increased risk of head and neck cancer only when alcohol was consumed at high frequency (OR for three or more drinks per day versus never drinking = 2.04, 95% CI = 1.29 to 3.21). The association with high-frequency alcohol intake was limited to cancers of the oropharynx/hypopharynx and larynx.


CONCLUSIONS
Our results represent the most precise estimates available of the independent association of each of the two main risk factors of head and neck cancer, and they exemplify the strengths of large-scale consortia in cancer epidemiology.
Hashibe
Mia
M
Gene-Environment Epidemiology Group, International Agency for Research on Cancer, 150 cours Albert Thomas, 69008 Lyon, France. hashibe@iarc.fr
Brennan
Paul
P
Benhamou
Simone
S
Castellsague
Xavier
X
Chen
Chu
C
Curado
Maria Paula
MP
Dal Maso
Luigino
L
Daudt
Alexander W
AW
Fabianova
Eleonora
E
Fernandez
Leticia
L
Wünsch-Filho
Victor
V
Franceschi
Silvia
S
Hayes
Richard B
RB
Herrero
Rolando
R
Koifman
Sergio
S
La Vecchia
Carlo
C
Lazarus
Philip
P
Levi
Fabio
F
Mates
Dana
D
Matos
Elena
E
Menezes
Ana
A
Muscat
Joshua
J
Eluf-Neto
Jose
J
Olshan
Andrew F
AF
Rudnai
Peter
P
Schwartz
Stephen M
SM
Smith
Elaine
E
Sturgis
Erich M
EM
Szeszenia-Dabrowska
Neonilia
N
Talamini
Renato
R
Wei
Qingyi
Q
Winn
Deborah M
DM
Zaridze
David
D
Zatonski
Witold
W
Zhang
Zuo-Feng
ZF
Berthiller
Julien
J
Boffetta
Paolo
P
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects*; D016022:Case-Control Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000139:chemically induced*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*