Vitamin D deficiency in men may be linked to an aggressive form of prostate cancer, according to a new study recently published in the Journal of Clinical Oncology.Researchers analyzed the medical records of 190 men whose prostates were removed due to cancer. All the men were around 64-years-old and had a prostatectomy sometime between 2009 and 2014.

High rate of cancer linked to low vitamin D

The study results showed that 46% of the men had very advanced prostate cancer and low levels of vitamin D. The 87 men in the group with the aggressive cancer had a median level of 22.7 nanograms per milliliter of vitamin D.

A level considered normal is 30 nanograms or above per milliliter.

In previous studies done by the same research team, vitamin D levels were checked and found to be low just days before prostate surgery. However, the new study looked at levels several months before surgery and also found a vitamin D deficiency, confirming a connection between the two.

Information from this research has led the scientists to believe a vitamin D deficiency could help predict aggressive prostate cancer before surgery is required. Defined by a high Gleason score, aggressive prostate cancer means the disease has progressed beyond the prostate gland. A Gleason score compares cancer tissue to normal prostate tissue and predicts the likelihood of the disease spreading.

"If men with vitamin D deficiency are more likely to have [more advanced disease] at the time of prostate surgery, then perhaps men should be tested for this when they are diagnosed with prostate cancer and subsequently supplemented with vitamin D if they are deficient," said researcher Adam Murphy, from Northwestern University Feinberg School of Medicine.

Other studies have indicated that dark-skinned men have a higher chance of vitamin D deficiency when living in low sunlight locations. Murphy says this could make a man more vulnerable to prostate cancer.

"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," said Murphy.

"Then a deficiency should be corrected with supplements."

Deficiency does not cause cancer

While a link between low vitamin D and prostate cancer may have been established, it does not prove that a vitamin D deficiency causes the disease.

Dr. Anthony D’Amico, chief of radiation oncology at Brigham and Women’s Hospital says there may be a link, but further testing is needed before jumping to conclusions. He doesn’t believe there is enough proof yet to confirm that supplements would decrease prostate cancer rates or make the disease any less aggressive.

When humans are exposed to direct sunlight, the body naturally manufactures vitamin D. The body also absorbs the nutrient when consuming fortified food like milk, orange juice, and cereal as well as some fish like salmon.

Roughly one in seven men will be diagnosed with prostate cancer at some point in their lifetime, according to the American Cancer Society. The low vitamin D and prostate cancer study can help men and health practitioners monitor and potentially slow the disease instead of opting for prostate removal surgery.