Men with low levels of vitamin D may have higher odds of developing aggressive prostate cancer, a new Northwestern University study has found.
The research, published in the Journal of Clinical Oncology, suggests checking for vitamin levels at the time a man undergoes surgery for prostate cancer may help doctors predict how life-threatening the disease may become.
That, in turn, can offer guidance to men and their doctors who may be considering active surveillance — in which they simply monitor the cancer — rather than remove the prostate through surgery.
"Vitamin D deficiency may predict aggressive prostate cancer as a biomarker," said lead researcher Dr. Adam Murphy, an assistant professor of urology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine urologist. "Men with dark skin, low vitamin D intake, or low sun exposure should be tested for vitamin D deficiency when they are diagnosed with an elevated PSA or prostate cancer. Then a deficiency should be corrected with supplements."
The link between vitamin D and prostate cancer may explain some disparities seen in prostate cancer, especially among African American men. Prior research by Murphy and colleagues showed African American men who live in low sunlight locations are up to 1.5 times more likely to have vitamin D deficiency than white men.
But because vitamin D is a biomarker for bone health and aggressiveness of other diseases, all men should check their levels, Murphy said.
"All men should be replenishing their vitamin D to normal levels," Murphy said. "It's smart preventive health care."
The new study involved 190 Chicago-are men, who underwent a radical prostatectomy to remove their prostate from 2009 to 2014.
Of that group, 87 men had aggressive prostate cancer. Those with aggressive cancer had a median level of 22.7 nanograms per milliliter of vitamin D, significantly below the normal level of more than 30 nanograms/milliliter. The average D level in Chicago during the winter is about 25 nanograms/milliliter, Murphy noted.
Most people in Chicago should be on D supplements, particularly during winter months, Murphy said.
"It's very hard to have normal levels when you work in an office every day and because of our long winter," he said. The Institute of Medicine recommends 600 international units of D per day, but Murphy recommends Chicago residents get 1,000 to 2,000 international units per day.