• Epidemiology Research Program, American Cancer Society, Atlanta, GA, USA, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA, Division of Cancer Etiology, Department of Population Sciences, Beckman Research Institute of the City of Hope, Duarte, CA, USA, Cancer Prevention Institute of California, Berkeley, CA, USA, Department of Medical Epidemiology and Biostatistics, Karolinska Insitutet, Stockholm, Sweden, Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway, Department of Research, Cancer Registry of Norway, Oslo, Norway, Samfundet Folkhälsan, Helsinki, Finland, Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Nashville, TN, USA, Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA, Department of Epidemiology, German Institute of Human Nutrition, Potsdam-Rehbruecke, Germany, Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA, Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA, Department of Population Health and Laura and Isaac Perlmutter Cancer Center, NYU School of Medicine, New York, NY, USA Social & Scientific Systems, Durham, NC, USA, Department of Epidemiology, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, P.R. China, Division of Aging, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA, Veteran's' Affairs Boston Healthcare System, Boston, MA, USA, Cancer Epidemiology Centre, Cancer Council Victoria, and Centre for Epidemiology and Biostatistics, University of Melbourne, VIC, Australia, Department of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, Division of Public Health Sciences, School of Medicine, Washington Universi

BACKGROUND: Associations between anthropometry and head and neck cancer (HNC) risk are inconsistent. We aimed to evaluate these associations while minimizing biases found in previous studies.

METHODS: We pooled data from 1,941,300 participants, including 3760 cases, in 20 cohort studies and used multivariable-adjusted Cox proportional hazard regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of anthropometric measures with HNC risk overall and stratified by smoking status.

RESULTS: Greater waist circumference (per 5 cm: HR = 1.04, 95% CI 1.03-1.05, P-value for trend = <0.0001) and waist-to-hip ratio (per 0.1 unit: HR = 1.07, 95% CI 1.05-1.09, P-value for trend = <0.0001), adjusted for body mass index (BMI), were associated with higher risk and did not vary by smoking status (P-value for heterogeneity = 0.85 and 0.44, respectively). Associations with BMI (P-value for interaction = <0.0001) varied by smoking status. Larger BMI was associated with higher HNC risk in never smokers (per 5 kg/m(2): HR = 1.15, 95% CI 1.06-1.24, P-value for trend = 0.0006), but not in former smokers (per 5 kg/m(2): HR = 0.99, 95% CI 0.93-1.06, P-value for trend = 0.79) or current smokers (per 5 kg/m(2): HR = 0.76, 95% CI 0.71-0.82, P-value for trend = <0.0001). Larger hip circumference was not associated with a higher HNC risk. Greater height (per 5 cm) was associated with higher risk of HNC in never and former smokers, but not in current smokers.

CONCLUSIONS: Waist circumference and waist-to-hip ratio were associated positively with HNC risk regardless of smoking status, whereas a positive association with BMI was only found in never smokers.