Does Prostate Volume Correlate with Vitamin D Deficiency Among Men Undergoing Prostate Biopsy?

OBJECTIVES: Recent studies demonstrate vitamin D is inversely correlated with benign prostatic hyperplasia (BPH) and prostate cancer (PCa) incidence. We aim to clarify the associations of vitamin D with prostate volume. METHODS: This is an observational study investigating the associations of serum PSA, PSA Density (PSAD) and prostate volume with serum 25-hydroxyvitamin D (25-OH D) in PCa patients and men with negative biopsies seen in outpatient urology clinics in Chicago, IL. There were 571 men (40- to 79-years-old) with elevated PSA or abnormal digital rectal examination (DRE) with available prostate volume recorded from initial biopsy. The primary outcomes were the unadjusted associations of serum 25-hydroxyvitamin D deficiency with prostate volume. The secondary outcomes were the adjusted associations using linear and logistic regression analysis. RESULTS: On univariate analysis, serum 25-OH D < 20ng/ml inversely correlated with prostate volume among all men undergoing transrectal ultrasonography (p = 0.02), and this relationship remained significant for men with negative biopsy on stratified analysis. In adjusted models, controlling for age, serum PSA, 5-ARI use, obesity, and PCa diagnosis, prostate volume was inversely associated with vitamin D (p < 0.05) using serum vitamin D as a continuous and categorical variable. Logistic regression model also demonstrated an inverse association between vitamin D (continuous and categorical) and prostate volume ≥ 40 grams. CONCLUSION: Serum 25-OH D levels are inversely associated with overall prostate volume and enlarged prostate gland (≥ 40 grams), especially in men with benign prostatic disease. Given the largely non-toxic effect of supplementation, consideration should be given to assessing vitamin D levels in men with benign prostatic disease in addition, to malignant prostatic disease.