Bone turnover markers and sex hormones in men with idiopathic osteoporosis

Authors


Department of Pathophysiology, University of Vienna, Austria (P. Pietschmann, M. Peterlik); Division of Rheumatology, Department of Medicine III, University of Vienna, Austria (P. Pietschmann, J. Grisar); Ludwig Boltzmann Institute of Aging Research, Vienna, Austria (P.Pietschmann, R. Willvonseder); Department of Medicine, Krankenhaus Barmherzige Brüder, Vienna, Austria (S. Kudlacek, R. Willvonseder); Department of Medical and Chemical Laboratory Diagnostics, University of Vienna, Austria (S. Spitzauer); Ludwig Boltzmann Institute of Experimental Endocrinology, Vienna, Austria (W. Woloszczuk).Correspondence to: Peter Pietschmann, MD, Associate Professor, Department of Pathophysiology, Waehringer Guertel 18–20, A-1090 Vienna, Austria. Tel.: + 43 140400 5122; fax: + 43 140400 5130; e-mail: peter.pietschmann@akh-wien.ac.at

Abstract

Background In contrast to osteoporosis in postmenopausal women, osteoporosis in men has received much less attention.

Patients and We determined various biochemical parameters of bone metabolism and sex hormones in 31 men with idiopathic osteoporosis and 35 age matched control subjects.

Results In the men with osteoporosis, a significantly increased urinary excretion of deoxypyridinoline (5·3 ± 0·2 vs. 4·6 ± 0·2 nmol mmol−1 creatinine; P = 0·033) in addition to increased serum levels of the c-terminal telopeptide of type I collagen (2677 ± 230 vs. 2058 ± 153 pmol; P = 0·037) were found. While parameters of bone formation were not significantly different in the patients and controls, serum bone sialoprotein levels were significantly decreased in the patients (3·7 ± 0·8 vs. 12·4 ± 4·0 ng mL−1; P = 0·021). Moreover, in men with idiopathic osteoporosis, lower levels of estradiol (91·3 ± 5·8 vs. 114·6 ± 7·8 pmol L−1; P = 0·044), higher levels of sex hormone binding globulin (31·5 ± 3·1 vs. 24·2 ± 1·4 nmol L−1; P = 0·034) and a decreased free androgen index (42·6 ± 5·2 vs. 56·4 ± 5·9; P = 0·016) were seen. Serum estradiol levels correlated negatively with several parameters of bone resorption.

Conclusions In men with idiopathic osteoporosis, bone resorption is increased and exceeds bone formation. The excessive bone resorption seen in idiopathic male osteoporosis may be due to decreased estradiol levels and low levels of bioavailable testosterone.

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