Endocrine Abstracts

Objective: 25-OH vitamin D3 (D3) possibly affects testosterone production. In some cross sectional studies the level of D3 correlates positively with total testosterone (TT) and free androgen index (FAI). In the European Male Ageing Study positive association of D3 with secondary and compensated hypogonadism was confirmed.

Aim: The aim of the study was to determine the relationship between D3 levels and levels of TT, LH, FSH and FAI in men. Secondary aim was to assess seasonality of measured values of D3, TT a FAI.

Methods: In 72 men with average age 68 years admitted to 5th Deparment of Internal Medicine we determined levels of D3 by chromatograhy, TT, LH and FSH by electrochemiluminescence and calculated FAI (TT/SHBG×100). Patients with severe liver disease, malignancy, antiandrogen therapy and vitamin D3 supplements were excluded. The correlation statistic was done by MedCalc system for all measured values and specifically for values in physiological range.

Results: The average level of TT was 13.3 nmol/l (interval 1–31.7 nmol/l), FAI 37% (10–88.2%), FSH 9.3 IU/l (1.3– 41.1), LH 7.3 IU/l (2.1–34.1) and D3 23.1 μg/l (4 52.5 μg/l). We did not cofirme correlation of D3 with androgen levels in whole group. In subgroup with values in physiological range we found negative correlation of D3 with FSH (r=0.11, P=0.02) and LH (r=0.1, P=0.02). We found insignificantly higher levels of TT in summer comparing with winter but we did not find any seasonality in FAI and D3 levels.

Conclusion: In our study we did not confirme correlation of D3 with TT, FAI, FSH and LH in whole group but we confirmed negative correlation of D3 and FSH and LH in subgroup with values in physiological range. In this sample, we confirmed association of D3 levels and compensated hypogonadism similarly as in European Male Ageing Study.