Association of alcohol intake over the lifetime with colorectal adenoma and colorectal cancer risk in the PLCO Cancer Screening Trial

The association of lifetime alcohol consumption with colorectal adenoma and colorectal cancer (CRC) is not clear. US adults enrolled in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial reported alcohol intake during four age periods. Average lifetime alcohol intake was calculated as average drinks per week from age 18 years until study baseline. Among 12,327 participants with a negative baseline screen, 812 had an adenoma on the second screen. During 20 years of follow-up, 1679 incident CRC cases occurred among 88,092 particpants. Current drinkers with an average lifetime alcohol intake of 14 or more drinks per week, compared with one drink or less per week, had a higher risk of CRC (HR 1.25; 95% CI 1.01-1.53), especially rectal cancer (HR 1.95; 95% CI 1.17-3.28). Consistent heavy drinking was positively associated with CRC risk (HR 1.91; 95% CI 1.17-3.12). Compared with current drinkers averaging less than one drink per week, former drinkers had lower odds of nonadvanced adenoma (OR 0.58; 95% CI 0.39-0.84). The authors conclude that consistent heavy alcohol intake and higher average lifetime alcohol drinking may increase CRC risk, whereas cessation may lower adenoma risk.