title: Physical activity and head and neck cancer risk.
abstract: OBJECTIVE
  To investigate the relation of physical activity to head and neck cancer.
  
  
  METHODS
  We prospectively examined the association between physical activity and head and neck cancer in 487,732 men and women, who, at baseline in 1995-1996, were 50-71 years old and free of cancer and emphysema. Follow-up occurred through 31 December 2003.
  
  
  RESULTS
  During follow-up, 1,249 participants developed head and neck cancer, of which 42.0%, 18.9%, and 32.5% were located in the oral cavity, pharynx, and larynx, respectively. In analyses adjusted for age and gender, the relative risks (RR) of head and neck cancer for increasing frequency of physical activity (0, < 1, 1-2, 3-4, and >or=5 times per week) were 1.0 (reference), 0.76, 0.66, 0.57, and 0.62 (95% CI = 0.52-0.74), respectively (p for trend < 0.001). After multivariate adjustment including smoking, the relation was attenuated and became statistically non-significant (RR comparing extreme physical activity categories = 0.89, 95% CI = 0.74-1.06; p for trend = 0.272). In analyses of head and neck cancer subtypes, the corresponding RRs for cancers of the oral cavity, pharynx, and larynx were 0.98 (95% CI = 0.75-1.29), 0.70 (95% CI = 0.45-1.08), and 0.82 (95% CI = 0.59-1.13), respectively.
  
  
  CONCLUSIONS
  Our findings suggest that physical activity is unlikely to play an important role in the prevention of head and neck cancer.
authors.affiliation: Department of Health and Human Services, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. leitzmann@mail.nih.gov
authors.forename: Michael F
authors.initials: MF
authors.lastname: Leitzmann
authors.forename: Corinna
authors.initials: C
authors.lastname: Koebnick
authors.forename: Neal D
authors.initials: ND
authors.lastname: Freedman
authors.forename: Yikyung
authors.initials: Y
authors.lastname: Park
authors.forename: Rachel
authors.initials: R
authors.lastname: Ballard-Barbash
authors.forename: Albert R
authors.initials: AR
authors.lastname: Hollenbeck
authors.forename: Arthur
authors.initials: A
authors.lastname: Schatzkin
authors.forename: Christian C
authors.initials: CC
authors.lastname: Abnet
mesh_terms: D000368:Aged; D000428:Alcohol Drinking; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000453:epidemiology* / Q000473:pathology; D006801:Humans; D015994:Incidence; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012042:Registries; D015203:Reproducibility of Results; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking; D011795:Surveys and Questionnaires; D013997:Time Factors; D014481:United States / Q000453:epidemiology