Alcohol consumption and upper aerodigestive tract squamous cell carcinoma: evidence from 28 prospective cohorts.

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 (grams/day) and UADT cancers 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, 6,903 UADT cancer cases were identified. Alcohol consumption was positively associated with UADT cancers risk overall. Even at intakes as low as 5-<15 g/day the HR estimate was 1.12 (95% CI 1.03,1.21) compared with the reference group (0.1-<5 g/day). The HR10g/day (95% CI) was 1.16 (1.14,1.18) for women and 1.12 (1.11,1.13) for men (pheterogeneity<0.0001). HR10g/day estimates were 1.14 (1.13,1.15) in current, 1.10 (1.09,1.12) in former, and 1.15 (1.12,1.18) in never-smokers. Consistent UADT HR10g/day estimates were observed across all beverage types. HR10g/day estimates varied across geographic regions, with HR10g/day (95% CI) equal to 1.15 (1.14,1.17) in Europe-Australia, 1.13 (1.11,1.15) in Asia, and 1.11 (1.09,1.12) in North America (pheterogeneity<0.0001). 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.