Vitamin D deficiency was an indicator of aggressive prostate cancer and spread of the disease in European-American and African-American men who underwent their first prostate biopsy after abnormal prostate-specific antigen (PSA) and/or digital rectal examination (DRE) test results, according to a study published in Clinical Cancer Research.
Between 2009 and 2013, researchers enrolled 667 men, ages 40 to 79 years, who were undergoing their first prostate biopsy following an abnormal PSA or DRE. Serum 25-OH D levels were measured at recruitment. Of participants, 273 were African-American and 275 were European-American, and 168 from each group had a prostate cancer diagnosis from their biopsy.
European-American and African-American 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, if their 25-OH D levels were < 12 ng/ml at the time of biopsy. In addition, African Americans had 2.43 times increased odds of being diagnosed with prostate cancer, if their 25-OH D levels were < 20 ng/ml. The researchers found that the mean 25-OH D levels were significantly lower among African Americans (16.7 ng/ml) compared with European Americans (19.3 ng/ml).
They categorized the study group into those whose 25-OH D levels were < 12 ng/ml, < 16 ng/ml, < 20 ng/ml, and < 30 ng/ml, and found a dose-response relationship between tumor grade and vitamin D level for both European Americans and African Americans. The association held true even after adjusting for potential confounders.
While no association was found between vitamin D deficiency and prostate cancer diagnosis in European Americans, this association was significant in African Americans. Further, the association with disease aggressiveness and cancer spread was stronger for African Americans. Skin color, which determines cumulative vitamin D levels from exposure to sun, may partly explain the discrepancies observed. Read the study abstract.Read more