Interestingly, the researchers didn’t find a significant association between total vitamin D intake and risk of colorectal cancer diagnosed after age 50.
The findings were not able to explain this inconsistency, and the scientists said further research in a larger sample is necessary to determine if the protective effect of vitamin D is actually stronger in young-onset colorectal cancer.
The researchers concluded that higher total vitamin D intake is associated with decreased risks of young-onset colorectal cancer and precursors (polyps).
“Vitamin D has known activity against colorectal cancer in laboratory studies,” said Dr Ng, director of the Young-Onset Colorectal Cancer Center at Dana-Ferber.
He continued: “Because vitamin D deficiency has been steadily increasing over the past few years, we wondered whether this could be contributing to the rising rates of colorectal cancer in young individuals.
“We found that total vitamin D intake of 300 IU per day or more – roughly equivalent to three 8-oz. glasses of milk – was associated with an approximately 50 percent lower risk of developing young-onset colorectal cancer.
“It is critical to understand the risk factors that are associated with young-onset colorectal cancer so that we can make informed recommendations about diet and lifestyle, as well as identify high risk individuals to target for earlier screening.”