Each year, approximately 104,270 new cases of colon cancer and 45,230 cases of rectal cancer are diagnosed in the United States. One in every 23 men will be diagnosed with colorectal cancer in their lifetime, as will one in 25 women, making the disease the third leading cause of cancer-related death in the U.S. among individuals of any gender. That's why it's so important for people to reduce their risk factors, including moving more, quitting smoking, and maintaining a healthy body weight. However, there's one surprising dietary factor—and an easily modifiable one, at that—a new study found to be significantly associated with early-onset colon cancer risk: eating red meat.
In a new paper published in the June 2021 volume of JNCI Cancer Spectrum, researchers compiled data from 3,767 individuals under 50 with early-onset colorectal cancer and 4,049 members of a control population across 13 studies, as well as 23,437 individuals over the age of 50 with colorectal cancer and 35,311 members of an over-50 control group.
Among the younger individuals with colorectal cancer, higher consumption of red meat was associated with a 10% increase in disease risk. Previously-identified factors that increase colorectal cancer risk in the general population, including smoking and high BMI, were not found to increase colorectal cancer risk among individuals under 50.
Surprisingly, alcohol intake, which has long been established as a risk factor for colorectal cancer by the American Cancer Society, was a double-edged sword in terms of early-onset colorectal cancer risk. Individuals with heavier alcohol use—classified as more than two drinks a day—were more likely to develop early-onset colorectal cancer, but individuals who abstained from alcohol completely also had a higher risk of developing the disease.
Additionally, researchers found that study subjects who didn't regularly take aspirin were more likely to develop early-onset colorectal cancer. Individuals with a history of diabetes, as well as those who consumed lower levels of folate, calcium, and fiber were all more likely to develop early-onset colorectal cancer, although a low-fiber diet was a more common predictor of rectal cancer than colon cancer.
"This first large-scale study of non-genetic risk factors for early-onset colorectal cancer is providing the initial basis for targeted identification of those most at risk, which is imperative in mitigating the rising burden of this disease," said Richard B. Hayes, DDS, MPH, Ph.D., a professor of population health and environmental medicine at NYU Langone Health and the study's lead author, in a statement.