Assessment of Vitamin D Status in Male Osteoporosis
Open Access
- 1 February 2006
- journal article
- Published by Oxford University Press (OUP) in Clinical Chemistry
- Vol. 52 (2), 248-254
- https://doi.org/10.1373/clinchem.2005.059568
Abstract
Background: Clinical assessment of vitamin D status often relies on measuring total circulating 25-hydroxyvitamin D3 (25OHD3), but much of each vitamin D metabolite is bound to plasma vitamin D–binding protein (DBP), such that the percentage of free vitamin is very low. We hypothesized that measurement of free rather than total 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and 25OHD3 may provide better assessment of vitamin D status. We therefore aimed to assess vitamin D status in men with idiopathic osteoporosis, in whom possible secondary causes of osteoporosis had been excluded, and to determine the extent of change in biologically active “free” vitamin D caused by variation in plasma DBP concentrations. Methods: We measured 1,25(OH)2D3 and 25OHD3 in plasma samples from 56 men with idiopathic osteoporosis [mean (SD) age, 59.6 (13.6) years; range, 21–86 years] and 114 male controls [62.4 (10.4) years; range, 44–82 years]. Results: Mean total plasma 25OHD3 in the 56 men with osteoporosis and the 114 controls was 44.7 (21) and 43.3 (17) nmol/L, respectively; total plasma 1,25(OH)2D3 measured in randomly selected men with osteoporosis (n = 50) and controls (n = 50) was 90 (37) and 103 (39) pmol/L, respectively. Mean plasma DBP was significantly higher (P <0.001) in men with osteoporosis [224 (62) mg/L; n = 56] than in the controls [143 (34) mg/L; n = 114], but calculated free plasma 25OHD3 and 1,25(OH)2D3 were significantly lower in the osteoporotic men than in controls [6.1 (3.1) vs 9.1 (4.4) pmol/L (P <0.00001) and 77 (37) vs 142 (58) fmol/L (P <0.00001), respectively]. Conclusions: Measurement of total vitamin D metabolites alone, although providing a crude assessment of vitamin D status, may not give an accurate indication of the free (biologically active) form of the vitamin. The ratio of total 25OHD3 and 1,25(OH)2D3 to plasma DBP, rather than total circulating vitamin D metabolites, may provide a more useful index of biological activity. Further studies are required to substantiate this hypothesis.Keywords
This publication has 26 references indexed in Scilit:
- Characterisation of cytosolic FK506 binding protein 12 and its role in modulating expression of Cbfa1 and osterix in ROS 17/2.8 cellsBone, 2005
- Vitamin D and autoimmune diabetesJournal of Cellular Biochemistry, 2003
- Vitamin D: its role and uses in immunology1The FASEB Journal, 2001
- High Prevalence of Vitamin D Deficiency in Japanese Female Patients with Graves' Disease.Endocrine Journal, 2001
- Vitamin D and Autoimmunity: Is Vitamin D Status an Environmental Factor Affecting Autoimmune Disease Prevalence?Proceedings of the Society for Experimental Biology and Medicine, 2000
- Vitamin D and Multiple SclerosisExperimental Biology and Medicine, 1997
- Vitamin D metabolism and bone mineralization in children with juvenile rheumatoid arthritisThe Journal of Pediatrics, 1994
- Vitamin D Binding Protein (Gc-Globulin)*Endocrine Reviews, 1989
- New Aspects of the Plasma Carrier Protein for 25‐Hydroxycholecalciferol in VertebratesAnnals of the New York Academy of Sciences, 1988
- Free 1,25-dihydroxyvitamin D levels in serum from normal subjects, pregnant subjects, and subjects with liver disease.JCI Insight, 1984