Tobacco, alcohol, body mass index, physical activity, and the risk of head and neck cancer in the prostate, lung, colorectal, and ovarian (PLCO) cohort.

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.