• Division of Public Health, Department of Family & Preventive Medicine and Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA. mia.hashibe@utah.edu

BACKGROUND: Estimation of attributable fractions for tobacco and alcohol, and investigation of the association between body mass index (BMI) and head and neck cancer risk have largely been in case-control studies. These aspects and physical activity need to be assessed as possible head and neck cancer risk/protective factors in a cohort study.

METHODS: In the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial, of the 101,182 study subjects, 177 individuals developed head and neck cancer.

RESULTS: The proportion of head and neck cancer cases attributed to tobacco and/or alcohol was 66% (50.5% tobacco alone, 14.7% alcohol alone, 0.9% tobacco and alcohol combined). BMI was not associated with head and neck cancer risk, but increasing hours of physical activity per week was associated with a reduced head and neck cancer risk (odds ratio [OR] = 0.58; 95% confidence interval [CI] = 0.35-0.96).

CONCLUSIONS: Cigarette smoking is clearly the most important head and neck cancer risk factor in this population. The reduced cancer risk due to physical activity was consistent with results from a pooled analysis of case-control studies.