A new epidemiological study reported today finds that consistent heavy alcohol consumption over a lifetime is associated with a significantly increased risk of colorectal cancer, particularly rectal cancer, while reducing or quitting drinking may lower that risk. The findings were published online in the peer-reviewed journal Cancer.
Researchers analyzed data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, following more than 88,000 U.S. adults without cancer at the study’s baseline for over 20 years. During this period, 1,679 participants developed colorectal cancer. Compared with individuals who consumed less than one alcoholic drink per week on average, those who drank 14 or more drinks weekly throughout adulthood faced about a 25% higher risk of colorectal cancer and an almost double risk of rectal cancer.
The study also highlighted that people who maintained heavy drinking habits consistently over many years were at even higher risk of developing colorectal cancer than lighter drinkers, demonstrating the importance of long-term consumption patterns in disease risk.
Importantly, the research offered a hopeful message: former drinkers did not show an elevated cancer risk compared to light drinkers, suggesting that reducing or stopping alcohol intake could potentially lower colorectal cancer risk. Researchers cautioned, however, that the data on people who had quit drinking was more limited and further studies are needed to confirm these trends.
Scientists propose several biological mechanisms that may underlie the observed association, including carcinogenic byproducts of alcohol metabolism and alcohol-induced changes to gut microbiota, though further research is needed to clarify these pathways.
The study adds to a growing body of evidence linking lifestyle factors like alcohol use to cancer risk, underscoring the value of public health strategies that encourage moderation and early cancer screening, especially among populations with a history of heavy drinking.
