Abstract
BACKGROUND: Association between light to moderate alcohol consumption and colorectal cancer (CRC) incidence remains understudied, especially regarding drinking pattern, beverage type, and temporal aspects. METHODS: Hazard ratios (HRs) and 95% confidence intervals (CIs) for time to CRC diagnosis were estimated among 137 710 participants. Estimates based on remote (eg, >10 years before follow-up) and recent (eg, the preceding 10 years before follow-up) alcohol intake, using different cutoffs (eg, 8, 10, 12 years) and mutual adjustment, enabled separating independent effects and investigating time lag of alcohol-CRC association. RESULTS: In total, 3599 CRC cases were documented over 3 decades. Light to moderate drinking was associated with an increased CRC risk only in men: HR (95% CI) for 5-14.9 and 15-29.9 vs 0 g/day of alcohol intake was 1.19 (1.01 to 1.41) and 1.38 (1.13 to 1.67). In women, that for 0.1-4.9 and 5-14.9 vs 0 g/day of alcohol was 1.07 (0.96 to 1.20) and 1.05 (0.91 to 1.20). Drinkers with both high drinking frequency and daily intake had the highest CRC risk, suggesting total alcohol intake was the critical factor. We estimated the time lag between alcohol consumption and CRC occurrence to be 8 to 12 years. Former drinkers did not experience a significant reduction in CRC risk even after 10 years of quitting or reducing consumption. CONCLUSIONS: Based on 2 cohorts of health professionals, our findings suggest that the increased risk of CRC associated with alcohol intake is driven mainly by total quantity and remote intake. Former drinkers did not experience an immediate reduction in CRC risk after quitting or reducing consumption.