European-American and African-American men who already have a high risk of aggressive prostate cancer may be at an even higher risk of developing the disease if they have a vitamin D deficiency.
"Vitamin D deficiency could be a biomarker of advanced prostate tumor progression in large segments of the general population," Adam B. Murphy, M.D., lead author of the study, said in a Northwestern University news release reported. "More research is needed, but it would be wise for men to be screened for vitamin D deficiency and treated."
"This is the first study to look at vitamin D deficiency and biopsy outcomes in men at high risk of prostate cancer," Rick Kittles, senior author of the study, said in the news release. "Previous studies focused on vitamin D levels in men either with or without prostate cancer."
To make their findings the researchers looked at data from over 600 men living in the Chicago area that had high PSA levels and other factors that increased their risk of prostate cancer. These subjects had been screened for vitamin D deficiencies before undergoing a biopsy.
The team found having a vitamin D deficiency put both African-American and European-American men at a higher risk of developing prostate cancer even if other risk factors such as smoking were adjusted for.
"These men, with severe vitamin D deficiency, had greater odds of advanced grade and advanced stage of tumors within or outside the prostate," Murphy said.
These men had "3.66 times and 4.89 times increased odds of having aggressive prostate cancer respectively and 2.42 times and 4.22 times increased odds of having tumor stage T2b or higher, respectively," the news release reported.
"Vitamin D deficiency is more common and severe in people with darker skin and it could be that this deficiency is a contributor to prostate cancer progression among African-Americans," Murphy said. "Our findings imply that vitamin D deficiency is a bigger contributor to African-American prostate cancer."
The researchers suggest getting vitamin D levels checked about once a year.
"It is a good idea to get your levels checked on a yearly basis," Murphy said. "If you are deficient, you and you doctor can make a plan on how to reverse it through diet, supplements or other therapies."
