LAUSR

Objectives:Recent studies demonstrate vitamin D is inversely correlated with 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 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, USA. There were 571 men (40–79 years old) with elevated PSA or abnormal digital rectal examination with available prostate volume recorded from initial biopsy. The primary outcomes were the unadjusted associations of serum 25-OH 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<20 ng ml−1 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-α reductase inhibitors 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.