Aug. 2, 2024 – People who drink alcohol, smoke, or have other unhealthy lifestyle habits, like poor diet and lack of exercise, may reduce their risk of cancer of the colon or rectum by taking aspirin, a new study suggests.
The findings are important as researchers seek ways to reduce the risk of colorectal cancers, which are the second-leading cause of cancer deaths in the U.S. and are being diagnosed more in younger adults. The findings were published today in JAMA Oncology.
The researchers sought to find out if certain groups of people may particularly benefit from taking aspirin. That’s because despite aspirin’s long-known role in protecting against colorectal cancer, the drug has also been linked to gastrointestinal bleeding, which has influenced whether it is recommended as a preventive medicine.
Aspirin can also be used to reduce pain or inflammation, and it can act as a blood thinner.
This latest study included data for more than 100,000 people in the U.S. who were followed for decades, answering surveys about their health and lifestyle habits. The average starting age of people in the study was just over 49 years old. People who took two or more standard-dose aspirin tablets (325 milligrams) weekly or who took low-dose aspirin (81 milligrams) daily were compared to people who didn’t take aspirin, and the researchers analyzed colorectal cancer risk based on things like having overweight or obesity, smoking, level of alcohol intake, physical activity, and diet.
People with the healthiest habits had similar colorectal cancer rates, whether they took aspirin or not. The healthiest lifestyle group’s colorectal cancer risk rate was 1.5% with aspirin and 1.6% without.
In contrast, people with the unhealthiest lifestyles had a notably lower risk if they took aspirin, compared to those who didn't take it. The unhealthy lifestyle group’s colorectal cancer risk rate was 2.1% with aspirin and 3.4% without. Smoking and high body mass index (an indicator of overweight or obesity) were mostly linked to a higher risk, the authors wrote.
“Our results show that aspirin can proportionally lower the markedly elevated risk in those with multiple risk factors for colorectal cancer,” lead author and gastroenterologist Daniel Sikavi, MD, said in a news release from Mass General Brigham in Boston. “In contrast, those with a healthier lifestyle have a lower baseline risk of colorectal cancer, and, therefore, their benefit from aspirin was still evident, albeit less pronounced.”
Aspirin may affect the development of cancer in more than one way, including how it impacts body processes involving inflammation, cell growth, immune response, and blood supply to cancer cells, Mass General Brigham summarized in its news release.
The study had important limitations, the authors noted, including that all the people studied worked in the health care industry, and most were White, so further study in a more diverse population is warranted. This latest study also did not evaluate potential side effects of aspirin use, such as bleeding.
