Abstract
BACKGROUND: This study aimed to investigate the association between alcohol consumption and squamous cell cancers of the upper aerodigestive tract (UADT), using data from 28 cohorts within the Pooling Project of Prospective Studies of Diet and Cancer (DCPP). METHODS: Individual-level data from 2 365 437 participants were pooled. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox models to quantify the association between alcohol consumption (g/day) and UADT cancer risk, adjusting for potential confounders. Analyses were conducted by sex, smoking status, geographic region, and alcoholic beverages. RESULTS: Over a median follow-up of 15.5 years, 6903 UADT cancer cases were identified. Alcohol consumption was positively associated with UADT cancer risk overall. Even at intakes as low as 5-<15 g/day, the HR estimate was 1.12 (95% CI = 1.03 to 1.21) compared with the reference group (0.1-<5 g/day). The HR10 g/day (95% CI) was 1.16 (1.14 to 1.18) for women and 1.12 (1.11 to 1.13) for men (Pheterogeneity < .0001). HR10 g/day estimates were 1.14 (1.13 to 1.15) in current, 1.10 (1.09 to 1.12) in former, and 1.15 (1.12 to 1.18) in never smokers. Consistent UADT HR10 g/day estimates were observed across all beverage types. HR10 g/day estimates varied across geographic regions, with HR10 g/day (95% CI) equal to 1.15 (1.14 to 1.17) in Europe-Australia, 1.13 (1.11 to 1.15) in Asia, and 1.11 (1.09 to 1.12) in North America (Pheterogeneity < .0001). CONCLUSION: Alcohol consumption was associated with UADT cancer risk, irrespective of smoking status or beverage type. However, due to differential baseline risks, alcohol is expected to impact the UADT cancer burden more in smokers than never smokers. These findings support public health strategies to reduce alcohol consumption.