Abstract 1873: Serum vitamin D levels and prostate volume
Authors: Kalu Richard U. , Murphy Adam B. , Nyame Yaw , Jordan Gregory A. , Kittles Rick A. 
Published: August 2015

Abstract
Introduction: We investigate the association between serum 25-hydroxyvitamin D (25-OH D) levels and prostate volume, PSA, and PSA density (PSAD) given literature linking vitamin D with prostate proliferation.
Procedures: From 2010-13, we enrolled 40-79 year old ambulatory men undergoing trans-rectal ultrasound (TRUS) guided prostate biopsy for elevated PSA or abnormal DRE from academic, outpatient urology clinics in Chicago, IL. Men with PSA &gt; 50ng/ml were excluded. Clinical and demographic data were collected by self-administered questionnaires and chart review. Venipuncture for serum 25-OH D and prostate volume estimation by the ellipsoid formula were done during TRUS. PSAD was calculated as the pre-biopsy serum PSA (ng/ml) divided by the prostate volume (cm3). The association of prostate volume, PSA, and PSAD with 25-OH D was assessed using univariate analysis of variance with 25-OH D as a categorical variable. Best fit linear regressions were constructed for multivariate analysis of this association adjusted for age, BMI, serum 25-OH D, PSA, 5-alpha reductase inhibitor (5-ARI), alcohol and tobacco use.
Results: We had 364 cases (median age 62.4) and 186 negative biopsies (NBx, median age 62.1, p = 0.046). European Americans comprised 41.4% of cases vs 39.3% of NBx (p = 0.55). Cases had more PCa family history (25.5 vs 14.4% in NBx, p = 0.0001) but had smaller prostate volume relative to NBx (35.4 vs 50.5cm3, p &lt;0.0001). On univariate analysis, serum 25-OH D was negatively associated with prostate volume and serum PSA and was statistically significant for the cases and negative biopsy groups. On linear regression, 25-OH D was negatively associated with prostate volume, PSA, and PSAD (Table 1).
Conclusion: Vitamin D is more strongly correlated with prostate volume than serum PSA. This suggests an anti-proliferative role for vitamin D in BPH/LUTS and PCa and warrants more study.
Funding: None
Table 1: Linear Regression Models for Prostate Volume, PSA and PSAD
Dependent VariablesProstate VolumeSerum PSAPSA Densityβ (CI)β (CI)β (CI)Independent VariablesPCaNBxPCaNBxPCaNBxAge*0.41 (0.09, 0.73)*1.01 (0.38, 1.65)0.03 (-0.09, 0.15)0.08 (-0.05, 0.21)-0.002 (-0.01, 0.002)-0.002 (-0.01, 0.001)BMI*0.64 (0.20, 1.1)*1.14 (0.16, 2.11)-0.07 (-0.23, 0.10)0.13 (-0.07, 0.34)*-0.01 (-0.01, -0.001)0.001 (-0.01, 0.01)25-OH D-0.13 (-0.34, 0.07)*-0.55 (-0.97, -0.14)-0.10 (-0.18, 0.02)*-0.08 (-0.16, 0.00)-0.001 (-0.003, 0.001)-0.001 (-0.004, 0.002)Serum PSA*0.29 (0.02, 0.56)*0.61 (-0.001, 1.22)----5-ARI use*8.60 (-1.13, 18.33)10.14 (-2.25, 22.53)5.57 (2.06, 9.08)*6.57 (3.93, 9.21)0.04 (-0.07, 0.15)0.06 (-0.02 - 0.14)Cig. Use*-7.13 (-11.51, -2.76)-9.53 (-19.10, 0.04)0.43 (-1.19, 2.06)0.32 (-1.64, 2.29)0.05 (-0.001, 0.10)0.02 (-0.05, 0.08)Alc. Use-1.55 (-8.44, 5.35)1.58 (-11.13, 4.29)-2.20 (-4.78, 0.39)-1.26 (-4.07, 1.55)-0.03 (-0.11, 0.05)-0.08 (-0.16, 0.01)
Covariates with * reached significance, p&lt;0.05.
Citation Format: Richard U. Kalu, Adam B. Murphy, Yaw Nyame, Gregory A. Jordan, Rick A. Kittles. Serum vitamin D levels and prostate volume. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1873. doi:10.1158/1538-7445.AM2015-1873