Anthropometry and head and neck cancer:a pooled analysis of cohort data.

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.