title: Minimal levels of serum estradiol prevent postmenopausal bone loss.
abstract: Biochemical parameters reflecting bone resorption [urinary calcium/creatinine (Ca/Cr) and hydroxyproline/creatinine (OH/Cr)] were related to serum estrogens [estrone (E1) and estradiol (E2)] in 262 healthy women including 158 patients receiving estrogen replacement therapy (ERT) for at least 6 months, 49 eugonadal women, and 55 untreated postmenopausal women. A significant (P < 0.001) correlation exists between serum E2 and Ca/Cr: Ca/Cr (mg/dl) = -0.00044 E2 (pg/ml) + 0.129 (n = 262; r = -0.37), serum E2 and OH/Cr: (OH/Cr (mg/g) = -0.049 E2 (pg/ml) + 18.76 (n = 262; r = -0.36), serum E1 and Ca/Cr: Ca/Cr (mg/dl) = -0.0003 E1 (pg/ml) + 0.127 (n = 261; r = -0.28) but not between serum E1 and OH/Cr. Women with circulating levels of E2 between 60 and 90 pg/ml have a significant (P < 0.01) reduction of Ca/Cr and OH/Cr when compared with those with lower levels of E2. Higher values of E2 do not provide additional benefit. We conclude that in postmenopausal women receiving an estrogen replacement therapy (ERT), a significant reduction of bone resorption is achieved when circulating levels of estradiol reach a value (60 pg/ml) corresponding to the one measured, in eugonadal women, during the last days of the early follicular phase of the menstrual cycle. We suggest that oral or percutaneous ERT should induce a minimal value of 60 pg/ml to prevent postmenopausal bone loss.
authors.affiliation: Bone Metabolism Unit, University of Liège, Belgium.
authors.forename: J Y
authors.initials: JY
authors.lastname: Reginster
authors.forename: N
authors.initials: N
authors.lastname: Sarlet
authors.forename: R
authors.initials: R
authors.lastname: Deroisy
authors.forename: A
authors.initials: A
authors.lastname: Albert
authors.forename: U
authors.initials: U
authors.lastname: Gaspard
authors.forename: P
authors.initials: P
authors.lastname: Franchimont
mesh_terms: D000704:Analysis of Variance; D001862:Bone Resorption / Q000517:prevention & control*; D002118:Calcium / Q000652:urine; D003404:Creatinine / Q000652:urine; D004958:Estradiol / Q000097:blood*; D015914:Estrogen Replacement Therapy; D004970:Estrone / Q000097:blood; D005260:Female; D006801:Humans; D006909:Hydroxyproline / Q000652:urine; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control*
chemical_list: D004970:Estrone; D004958:Estradiol; D003404:Creatinine; D006909:Hydroxyproline; D002118:Calcium