January - March 2007, Volume 3, Issue 1

Pop GD, Duncea I, Georgescu C, Hazi G, Dragotoiu G, Leucuta DC

Estimation of 25(OH)D levels required for maintaining a normal bone turnover in healthy aging men

Acta Endo (Buc) 2007, 3 (1): 31-44
doi: 10.4183/aeb.2007.31

Introduction. Vitamin D deficiency has been proven to have a deleterious effect on bone remodeling and bone mineral density, by inducing secondary hyperparathyroidism. The lack of a present consensus on optimal serum 25(OH)D levels required for the preservation of physiologic bone metabolism renders its follow-up difficult.\r\nMaterials and Methods. The cross-sectional study was performed on a sample of 69 healthy men aged 50-70. Serum 25(OH)D, total testosterone, sex hormone binding globulin, s-CTX (Crosslaps), and osteocalcin were assessed. BMD was measured by DXA at lumbar spine and hip levels. Statistical relationships between these parameters were calculated.\r\nResults. We found a significantly negative correlation between 25(OH)D and s-CTX (r = -0.30. p<0.05), but not between 25(OH)D and osteocalcin, although s-CTX correlated positively with osteocalcin (r = 0.49, p<0.001). Serum CTX was negatively correlated with lumbar BMD (r = -0.35, p<0.001), while osteocalcin was negatively correlated with total hip BMD (r = -0.26, p<0.01). Comparing mean s-CTX levels in insufficient and sufficient subjects at different cut-off points for 25(OH)D, significant differences appeared the strongest at 60 ng/ml. The percentage of 25(OH)D deficient or insufficient subjects was 50.7% at a 30 ng/ml cut-off point.\r\nConclusions. The results of the present study confirm the benefit in maintaining a normal bone turnover offered by serum 25(OH)D in the upper normal range. The large percentage of patients with vitamin D insufficiency reinforce the necessity of a specific follow-up and of epidemiologic studies dedicated to our geographic area.

Keywords: vitamin D insufficiency, osteoporosis in men, bone markers, aging men

Correspondence: George Dorin Pop, MD, "Iuliu Hatieganu" University of Medicine and Pharmacy Cluj-Napoca, Clinic of Endocrinology, Address: str. General Eremia Grigorescu Nr. 98, 400304 Cluj-Napoca, Romania, , Tel: 0723.278.914; Fax: 0264.439.258, E-mail: georgedorinpop@yahoo.fr