WASHINGTON, January 29, 2026 — A lifetime of happy hours could be raising your risk of colorectal cancer, and new research suggests the amount of alcohol consumed over decades matters significantly. The study, published online in CANCER, a peer-reviewed journal, found that heavy, long-term drinking is linked to a substantially increased risk, particularly for rectal cancer, but cutting back may offer some protection.
Lifetime Alcohol Intake Tied to Colorectal Cancer Risk
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New findings highlight the importance of considering cumulative alcohol consumption when assessing cancer risk.
- Heavy drinkers—those averaging 14 or more drinks per week—faced a 25% higher risk of colorectal cancer.
- The risk of rectal cancer nearly doubled for heavy drinkers, increasing by 95%.
- Former drinkers did not show an increased risk, and may even have a reduced risk of developing noncancerous tumors.
- The study analyzed data from nearly 88,000 U.S. adults over 20 years.
Researchers analyzed health data from 88,092 U.S. adults participating in the National Cancer Institute (NCI) Prostate, Long, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, all of whom were cancer-free at the study’s start. Over 20 years of follow-up, 1,679 participants were diagnosed with colorectal cancer.
Heavy Drinking Significantly Increases Risk
Among current drinkers, those who consistently consumed 14 or more drinks per week were classified as heavy drinkers. Compared to individuals who averaged less than one drink per week over their lifetime, heavy drinkers had a 25% higher risk of developing colorectal cancer. The impact was even more pronounced for rectal cancer, with their risk increasing by 95%—nearly doubling.
The study also examined drinking patterns over a person’s adult life. Individuals who drank heavily for many years had a 91% higher risk of colorectal cancer compared to those who consistently drank small amounts. Interestingly, former drinkers did not exhibit an increased risk of colorectal cancer. In fact, they had lower odds of developing noncancerous colorectal tumors, known as adenomas, compared to current drinkers who averaged less than one drink per week. These findings suggest that stopping alcohol consumption may offer a protective benefit, although researchers noted the data on former drinkers was limited.
Biological Mechanisms Under Investigation
The connection between alcohol use and increased cancer risk may be linked to harmful substances produced when the body metabolizes alcohol, or to alcohol’s impact on the gut microbiome. Further research is needed to fully understand whether these biological processes directly contribute to cancer development.
“Our study is one of the first to explore how drinking alcohol over the life course relates to both colorectal adenoma and colorectal cancer risk,” said co-senior author Erikka Loftfield, PhD, MPH, of the NCI, part of the National Institutes of Health. “While the data on former drinkers were sparse, we were encouraged to see that their risk may return to that of the light drinkers.”
