title: Carefully monitored levothyroxine suppressive therapy is not associated with bone loss in premenopausal women.
abstract: We measured total body and regional (lumbar spine, femoral neck, Ward's triangle, and trochanter) bone mineral density (BMD) in 47 premenopausal women chronically treated with suppressive doses of levothyroxine (L-T4). Treatment was administered to 7 patients with nontoxic goiter or, after thyroidectomy, to 38 patients with differentiated thyroid cancer and 2 with nontoxic goiter. Patients were followed at our institution and treated with the minimal amount of L-T4 necessary to suppress TSH. At the time of evaluation, free T3 was normal in all cases, whereas free T4 was increased in 17 (36.2%). The mean daily dose of L-T4 was 154.3 +/- 5 micrograms, and the mean duration of treatment was 10.1 yr. We found no significant difference between patients and age- and weight-matched controls in BMD at any site of measurement. BMD was not correlated with duration of therapy, cumulative or mean daily dose of L-T4, serum levels of free T4, free T3, and osteocalcin. There was no difference between patients and controls in serum total calcium, intact PTH, osteocalcin, or carboxy-terminal cross-linked telopeptide of type I collagen or in the concentrations of two markers of thyroid hormone action (sex hormone-binding globulin and amino-terminal propeptide of type III procollagen). Our data suggest that L-T4 suppressive therapy, if carefully carried out and monitored, using the smallest dose necessary to suppress TSH secretion has no significant effect on bone metabolism or bone mass.
authors.affiliation: Istituto di Endocrinologia, Università di Pisa, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Marcocci
authors.forename: F
authors.initials: F
authors.lastname: Golia
authors.forename: G
authors.initials: G
authors.lastname: Bruno-Bossio
authors.forename: E
authors.initials: E
authors.lastname: Vignali
authors.forename: A
authors.initials: A
authors.lastname: Pinchera
mesh_terms: D000328:Adult; D015519:Bone Density / Q000187:drug effects; D002118:Calcium / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005260:Female; D006042:Goiter / Q000188:drug therapy; D006801:Humans; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D010024:Osteoporosis / Q000097:blood / Q000139:chemically induced*; D010281:Parathyroid Hormone / Q000097:blood; D017697:Premenopause / Q000097:blood / Q000502:physiology*; D011347:Procollagen / Q000097:blood; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013964:Thyroid Neoplasms / Q000188:drug therapy; D013972:Thyrotropin / Q000037:antagonists & inhibitors*; D013974:Thyroxine / Q000009:adverse effects* / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use*; D013997:Time Factors; D014284:Triiodothyronine / Q000097:blood / Q000378:metabolism
chemical_list: D010281:Parathyroid Hormone; D011347:Procollagen; D012738:Sex Hormone-Binding Globulin; D014284:Triiodothyronine; D015675:Osteocalcin; D013972:Thyrotropin; D013974:Thyroxine; D002118:Calcium