OBJECTIVE: 17Beta-oestradiol (17beta-E2), mainly its bioavailable fraction (bio-17beta-E2), is a determinant of bone mineral density (BMD) and bone remodelling in men. As direct measurement of bio-17beta-E2 is time-consuming, we compared the value of directly measured bio-17beta-E2 and of calculated bio-17beta-E2 and free 17beta-E2 by studying their association with BMD and markers of bone turnover in a cohort of men (MINOS). DESIGN: A cross-sectional study in which the association between BMD and bone markers, on the one hand, and serum levels of 17beta-E2, on the other, was analysed according to the levels of measured and calculated bio-17beta-E2 and free 17beta-E2 in a cohort of men. SUBJECTS: Men from the MINOS cohort including 87 men aged 19-45 to establish the reference control normal range of hormones and 637 men aged 50-85 (studied group). MEASUREMENTS: Total 17beta-E2, testosterone, SHBG and albumin were measured by standard methods. bio-17beta-E2 was directly measured after the precipitation of SHBG by ammonium sulfate. bio-17beta-E2 and free 17beta-E2 were calculated using serum SHBG and albumin levels as described by Sodegard et al. (J. Steroid Biochem., 16 (1982) 801). RESULTS: Calculated bio-17beta-E2 and free 17beta-E2 were correlated with measured bio-17beta-E2 and between themselves (r = 0.90-1.00, P < 0.0001). Calculated bio-17beta-E2 and free 17beta-E2 disclosed a similar association with BMD (difference between lowest and highest quartiles of 17beta-E2: 2.6-6.8%, P < 0.05-0.005) to that of measured bio-17beta-E2 (3.6-6.1%, P < 0.005-0.001). The association between bone markers levels and measured vs. calculated 17beta-E2 were also similar. Predictive accuracy for lowered BMD and elevated levels of biochemical bone markers (evaluated using receiver operating characteristics) was relatively low (area under curve -0.582 to 0.709) but similar for different forms of bioavailable and free 17beta-E2. CONCLUSIONS: In elderly men, the concentrations of bioavailable and free 17beta-E2, calculated using equations including either the measured albumin concentration or the constant albumin concentration of 43 g/l, can be used, at least in clinical studies, instead of the bio-17beta-E2 concentrations measured after ammonium sulfate precipitation.
OBJECTIVE:17Beta-oestradiol (17beta-E2), mainly its bioavailable fraction (bio-17beta-E2), is a determinant of bone mineral density (BMD) and bone remodelling in men. As direct measurement of bio-17beta-E2 is time-consuming, we compared the value of directly measured bio-17beta-E2 and of calculated bio-17beta-E2 and free 17beta-E2 by studying their association with BMD and markers of bone turnover in a cohort of men (MINOS). DESIGN: A cross-sectional study in which the association between BMD and bone markers, on the one hand, and serum levels of 17beta-E2, on the other, was analysed according to the levels of measured and calculated bio-17beta-E2 and free 17beta-E2 in a cohort of men. SUBJECTS:Men from the MINOS cohort including 87 men aged 19-45 to establish the reference control normal range of hormones and 637 men aged 50-85 (studied group). MEASUREMENTS: Total 17beta-E2, testosterone, SHBG and albumin were measured by standard methods. bio-17beta-E2 was directly measured after the precipitation of SHBG by ammonium sulfate. bio-17beta-E2 and free 17beta-E2 were calculated using serum SHBG and albumin levels as described by Sodegard et al. (J. Steroid Biochem., 16 (1982) 801). RESULTS: Calculated bio-17beta-E2 and free 17beta-E2 were correlated with measured bio-17beta-E2 and between themselves (r = 0.90-1.00, P < 0.0001). Calculated bio-17beta-E2 and free 17beta-E2 disclosed a similar association with BMD (difference between lowest and highest quartiles of 17beta-E2: 2.6-6.8%, P < 0.05-0.005) to that of measured bio-17beta-E2 (3.6-6.1%, P < 0.005-0.001). The association between bone markers levels and measured vs. calculated 17beta-E2 were also similar. Predictive accuracy for lowered BMD and elevated levels of biochemical bone markers (evaluated using receiver operating characteristics) was relatively low (area under curve -0.582 to 0.709) but similar for different forms of bioavailable and free 17beta-E2. CONCLUSIONS: In elderly men, the concentrations of bioavailable and free 17beta-E2, calculated using equations including either the measured albumin concentration or the constant albumin concentration of 43 g/l, can be used, at least in clinical studies, instead of the bio-17beta-E2 concentrations measured after ammonium sulfate precipitation.
Authors: Marlies Bekaert; Yves Van Nieuwenhove; Patrick Calders; Claude A Cuvelier; Arsène-Hélène Batens; Jean-Marc Kaufman; D Margriet Ouwens; Johannes B Ruige Journal: Endocrine Date: 2015-03-13 Impact factor: 3.633
Authors: Frederique Van de Velde; Marlies Bekaert; Anne Hoorens; Anja Geerts; Guy T'Sjoen; Tom Fiers; Jean-Marc Kaufman; Yves Van Nieuwenhove; Bruno Lapauw Journal: Asian J Androl Date: 2020 May-Jun Impact factor: 3.285