Changes in lifestyle and dietary patterns may be partly to blame for the increasing incidence of colorectal cancer among younger adults.
Scientists have speculated that declines in average dietary intake of vitamin D since the 1980s may be a factor in this increased incidence.
A study has found an association between a higher total intake of vitamin D and a lower risk of colorectal cancer in adults under 50 years of age.
The findings suggest that encouraging people in this age group to increase their vitamin D intake could provide a cheap, low-risk complement to screening for the disease.
Colorectal cancer (cancer of the colon or rectum) is the third most common cancer Trusted Source and the third leading cause of cancer-related deaths in the United States.
While the overall incidence of colorectal cancer has decreased over the past 2 decades, the number of younger adults with the disease has increased.
If current trends continue, researchers estimate Trusted Source that by 2030 almost 11% of colon cancers and 23% of rectal cancers will occur in adults under 50 years of age.
Around half of the people with early-onset colorectal cancer do not have a family history of the disease or known genetic risk factors, so changing lifestyles and diet patterns may play a role in its increasing incidence.
They have also focused on changes in diet Trusted Source as another possible culprit for the rising numbers.
The researchers suggest that reduced consumptionTrusted Source of foods rich in vitamin D, such as dairy products, fish, mushrooms, and eggs, is one of the prime suspects.
Several studies have found that vitamin D protects against colorectal cancer overall, but none have focused on the early-onset form of the disease.
“Dietary changes in recent decades are one of the many potential risk factors that we are studying in relation to young-onset colorectal cancer,” said Kimmie Ng, M.D., M.P.H., who directs the Young-Onset Colorectal Cancer Center at the Dana-Farber Cancer Institute in Boston, MA.
“We know that diet and lifestyle are strongly linked to colorectal cancer overall (no matter what the age of diagnosis), so it makes sense to explore whether some of the risk factors that have changed recently — like vitamin D — may be contributing to the rise of young-onset colorectal cancer,” she told Medical News Today.
Dr. Ng and her colleagues at the Harvard T.H. Chan School of Public Health in Boston, MA, and other institutions analyzed data on the diet, lifestyle, and medical history of 116,429 female nurses aged 25–42 years old.