Is vitamin D associated with testosterone in benign prostate hyperplasia?

Abstract

Introduction. Benign prostate hyperplasia (BPH) affects about 50% of male population between 51-60 years and almost 90% of 81-90 aged males. It is considered that BPH pathogenesis involves epithelial cells and stromal tissue proliferation inside prostate gland and testosterone is one of the promoting factors of prostate cell growth. Evidences about the antiproliferative effects of vitamin D and the widespread vitamin D deficiency and insufficiency among Bulgarian population suggest a possible relation between vitamin D and testosterone in BPH patients. Aim. To evaluate the vitamin D status and total testosterone (TT) levels in BPH patients and their associations with laboratory parameters such as prostate specific antigen (PSA) for prostate growth. Materials and methods. A total of 37 male BPH patients (mean age 67,14±7,77 years) were enrolled in the study. In all patients, BPH was histologically proven. PSA and ТТ levels were analyzed immunochemically. The circulating form of vitamin D, 25-hydroxyvitamin D (25OHD) was assayed by liquid chromatography with mas-spectrometry detection (LC-MS/MS). Other covariates (BMI, age,) were collected by interview at the time of hospitalization. Classical biochemical parameters were assayed by routine spectrophotometric tests. Descriptive statistics, variation and non-parametric correlation analysis were used. The level of significance was set at p<0.05. Results. The mean level of 25OHD for BPH patients was close to the lower reference limit of 50nmol/L recommended by the US Endocrine Society Guideline. The majority of BPH patients (56.8%) display 25OHD levels above 50nmol/L, 43.2% of them were vitamin D deficient (25OHD < 50nmol/L), 8.1% – with severe vitamin D deficiency (25OHD <25nmol/L), and only 6 patients (16.2%) had optimal 25OHD levels above the limit of 75 nmol/L. The mean serum TT levels of BPH patients were 10.74 ± 4.026 nmol/L, close to the lower limit of 10.4 nmol/L for normal TT, according to the recommendations of the Endocrine Society. A significant seasonal variations were found for 25OHD levels (p<0.05) between the cold and warm season. Similar seasonality was not established for TT. Two-thirds of BPH patients (62.9%) were with PSA values below the upper limit of the reference interval of 4 ng/ml. Higher 25OHD levels (59.21 ± 3.756 nmol/l, p= 0.06) were established for the group with PSA below the threshold of 4ng/ml. A moderate negative correlation (Spearman r= -0.6707, p<0.01) was found only for the vitamin D deficient group. In case of vitamin D sufficiency, a weak positive trend was detected. Conclusion. Our study indicated vitamin D insufficiency in BPH patients according to the criteria of the Endocrine Society. Strong negative correlation between 25OHD and TT levels was found for vitamin D deficient BPH patients. Higher 25OHD were associated with lower PSA values indicating a potential favorable effect of 25OHD on slackening of BPH.