Severe Vitamin D Deficiency Is Associated With Aggressive Prostate Cancer, Study Finds
A study investigating vitamin D status and prostate cancer diagnosis in high-risk men has found an association between vitamin D deficiency and aggressive prostate cancer. The study enrolled 667 men, ages 40 to 79 years, who were undergoing their first prostate biopsy following an abnormal prostate-specific antigen (PSA) and/or digital rectal examination. In addition to their biopsy, on the date of enrollment, the men also had their serum 25-OH D (25-hydroxyvitamin D) level drawn. The researchers found that in African American men vitamin D deficiency was associated with increased odds of prostate cancer diagnosis on biopsy. In both European American and African American men, severe vitamin D deficiency was positively associated with higher Gleason grade and tumor stage. The study by Murphy et al is published in Clinical Cancer Research.
Study Findings
The study enrolled men between 2009 and 2013 from five urology clinics in Chicago, Illinois. European American and African American men were found to have 3.66-times and 4.89-times increased odds of having aggressive prostate cancer (Gleason grade of 4+4 or higher), respectively, and 2.42-times and 4.22-times increased odds of having tumor stage T2b or higher, respectively, if their 25-OH D levels were less than 12 ng/mL at the time of the biopsy. In addition, the African American men had 2.43-times increased odds of being diagnosed with prostate cancer if their 25-OH D levels were less than 20 ng/mL. The normal range of 25-OH D is between 30 and 80 ng/mL.
The researchers found that the mean 25-OH D levels were significantly lower among African American men (16.7 ng/mL) compared with European American men (19.3 ng/mL). The highest 25-OH D level was 71 ng/mL in European men, and only 45 ng/mL in African American men.
The researchers categorized the study volunteers into those whose 25-OH D levels were less than 12 ng/mL, less than 16 ng/mL, less than 20 ng/mL, and less than 30 ng/mL, and found a dose-response relationship between tumor grade and vitamin D level for both European American and African American men. This association remained true even after adjusting for potential confounders, including diet, smoking history, obesity, family history, and calcium intake.
The researchers also found that an association between lower 25-OH D levels and those at high and very high risk for prostate cancer based on National Comprehensive Cancer Network criteria, which take into account prediagnosis PSA levels, tumor stage, and Gleason grade.
Vitamin D Deficiency and Prostate Cancer in African American Men
While no association was found between vitamin D deficiency and prostate cancer diagnosis in the European American study participants, there was a significant association found in the African American participants. The association with disease aggressiveness and cancer spread was also stronger for the African American men, according to the study results.
“We will next evaluate genetic polymorphisms in the pathways of vitamin D metabolism to better understand the risk alleles underlying this association,” Adam B. Murphy, MD, MBA, lead author of the study and Assistant Professor in the Department of Urology at the Northwestern University Feinberg School of Medicine in Chicago, said in a statement. “Vitamin D deficiency seems to be important for general wellness and may be involved in the formation or progression of several human cancers. It would be wise to be screened for vitamin D deficiency and treated.”
Racial Disparities in Prostate Cancer
Although prostate cancer is the most common nondermatologic malignancy in men, there are significant racial disparities in incidence and mortality rates. According to the American Cancer Society, prostate cancer is 1.6 times more common among African American men and African American men are more than 2.5 times more likely to die of the cancer.
Dr. Murphy is the corresponding author of the Clinical Cancer Research article.
The study was funded by the National Institutes of Health and the U.S. Department of Defense. Dr. Murphy reported no conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
