Study Links Heavy Lifetime Alcohol Use to Higher Colorectal Cancer Risk

A recent study adds new evidence that heavy alcohol consumption sustained over adulthood is associated with a higher risk of colorectal cancer, particularly rectal cancer. 

The study, published in Cancer, looked at data from nearly 155,000 adults enrolled in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Researchers examined alcohol intake beginning at age 18 and followed participants over time to track the development of colorectal adenomas and cancer. 

Kathleen Egan, ScD, a cancer epidemiologist at Moffitt Cancer Center, says the study’s design strengthens confidence in the findings. 

Kathleen Egan, ScD

“This was a prospective study of healthy adults who were followed forward in time, which is a strong design from the standpoint of causal inference,” Egan said. “Importantly, the authors were able to look at alcohol exposure across the life course, not just at a single point in time.” 

Using current drinkers with low lifetime alcohol consumption as the reference group helped reduce potential bias, Egan notes, because lifetime abstainers may avoid alcohol due to underlying health conditions or lifestyle differences. 

The researchers found that people who averaged 14 or more drinks per week over their lifetimes had a statistically significant 25% higher risk of developing colorectal cancer, with most of the excess risk concentrated in rectal cancer. Lower levels of lifetime alcohol consumption among current drinkers did not show an increased risk, nor did drinking in any amount only in the past. 

The study also looked at how consistently heavy drinking occurred over time impacted risk. Heavy drinking was defined as more than two drinks per day for women and more than three drinks per day for men. Participants who met that criteria both in the past and at the time of enrollment had about twice the risk of colorectal cancer. Those with heavy drinking limited to only one period did not show an increased risk. 

“Looking at lifetime patterns is important because alcohol consumption can change with age, health and life circumstances,” Egan said. “Focusing only on recent drinking can misclassify cumulative exposure, which may be the most relevant factor for cancer risk.” 

Averaging more than 14 alcoholic drinks per week over a lifetime (two or more drinks per day) can significantly raise your chances of developing colorectal cancer, particularly rectal cancer, according to a large new study. Read the full findings from @EverydayHealth here 👉… pic.twitter.com/ifTDh9LICH

— Colorectal Cancer Alliance (@CCAlliance) January 27, 2026

Egan warns that the number of participants in some drinking categories was relatively small, limiting conclusions about lighter levels of consumption. The study also did not assess whether alcohol exposure earlier or later in life carries greater risk. 

Still, she says the findings align with decades of research linking heavy alcohol use to colorectal cancer. 

“The consistency of this association across many studies and populations strengthens the likelihood that this relationship is causal and not due to chance or bias,” Egan said. 

Alcohol is an established human carcinogen and is estimated to contribute to about 5% of cancers in the United States. While any amount of alcohol may increase cancer risk, Egan says the absolute risk associated with light or social drinking remains small. 

“It is also important to remember that colorectal cancer risk is influenced by multiple lifestyle factors, including smoking, diet, obesity and physical inactivity,” she said. “Maintaining a healthy lifestyle, drinking in moderation or not at all and following screening guidelines are effective ways to reduce risk.” 

Public health messaging around alcohol has increasingly emphasized moderation, a trend Egan says is reflected in declining alcohol consumption nationwide, particularly among young adults. 

“This is the same group that is experiencing rising rates of colorectal cancer,” she said. “We can hope that these shifts in behavior will ultimately have a positive impact on cancer rates.”