title: Effects of levothyroxine suppressive therapy on bone mineral density in premenopausal women.
abstract: BACKGROUND
  Levothyroxine (L-T4) is widely prescribed for treating thyroid disorders, but its effect on bone mineral density (BMD), is being debated.
  
  
  OBJECTIVE
  We studied the effect of supraphysiologic doses of L-T4 on BMD in a group of premenopausal women.
  
  
  METHODS
  We included 50 women (mean age=36.8 +/- 7.6 years) receiving L-T4 for at least 1 year for treating their benign cold thyroid nodules. Serum T3, T4, thyroid-stimulating hormone (TSH), parathyroid hormone (PTH), calcium, and phosphate and urine calcium and sodium levels of all patients were measured. Bone density at femoral neck and lumbar (L1-L4) regions was measured, using dual energy X-ray absorptiometry (DXA).
  
  
  RESULTS
  No significant decrease was detected in the bone density of the subjects treated with L-T4 compared with the control group.
  
  
  CONCLUSIONS
  L-T4 treatment for 1 year is not associated with increased risk of osteoporosis in premenopausal women but other potential adverse effects still need to be monitored in women receiving L-T4 especially long-term.
authors.affiliation: Internal Medicine, Tehran University of Medical Sciences, Tehran, Iran. emrc@sina.tums.ac.ir
authors.forename: B
authors.initials: B
authors.lastname: Larijani
authors.forename: F
authors.initials: F
authors.lastname: Gharibdoost
authors.forename: M
authors.initials: M
authors.lastname: Pajouhi
authors.forename: A
authors.initials: A
authors.lastname: Sadjadi
authors.forename: S
authors.initials: S
authors.lastname: Aghakhani
authors.forename: R
authors.initials: R
authors.lastname: Eshraghian
authors.forename: S M
authors.initials: SM
authors.lastname: Akrami
authors.forename: G
authors.initials: G
authors.lastname: Maalouf
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000187:drug effects*; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000187:drug effects; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000187:drug effects; D017697:Premenopause; D016606:Thyroid Nodule / Q000188:drug therapy; D013974:Thyroxine / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D013974:Thyroxine