title: Effects of hormonal replacement therapy on the postural balance among postmenopausal women.
abstract: OBJECTIVE
  To establish whether hormone replacement therapy affects postural balance in postmenopausal women.
  
  
  METHODS
  Nineteen healthy postmenopausal women with vasomotor symptoms were included. Median age was 54 years, median time since menopause was 3 years. They underwent dynamic posturography before and after 4 and 12 weeks of transdermal estrogen treatment (17 beta-estradiol 50 micrograms/day) as well as after 2 additional weeks of combined estrogen-progestagen treatment. The dynamic posturography method quantifies the amplitude, frequency, and pattern of body sway and tests the visual, vestibular, and somatosensory systems, which together maintain balance. The two most difficult tests either cancel visual and distort somatosensory inputs or give distorted information from both the visual and somatosensory systems.
  
  
  RESULTS
  Hormone replacement therapy increased static balance performance assessed by dynamic posturography. A highly significant improvement was seen in the two most difficult tests between the pretreatment test and the test performed after 4 weeks of estrogen therapy (P < .01, P < .001, respectively). This improvement was sustained after 12 weeks and also during the 14th week, with the women on combined estrogen-progestagen treatment.
  
  
  CONCLUSIONS
  Estrogen treatment increased balance performance measured by dynamic posturography, indicating that the beneficial effects from estrogens on postmenopausal fracture risk may include central nervous system effects on balance. Two weeks' addition of gestagen to the treatment regimen did not counteract the estrogen effects.
authors.affiliation: Department of Obstetrics and Gynaecology and Otolaryngology, Faculty of Health Sciences, University Hospital, Linköping, Sweden.
authors.forename: M L
authors.initials: ML
authors.lastname: Hammar
authors.forename: R
authors.initials: R
authors.lastname: Lindgren
authors.forename: G E
authors.initials: GE
authors.lastname: Berg
authors.forename: C G
authors.initials: CG
authors.lastname: Möller
authors.forename: M K
authors.initials: MK
authors.lastname: Niklasson
mesh_terms: D004958:Estradiol / Q000494:pharmacology* / Q000627:therapeutic use; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology; D004856:Postural Balance / Q000187:drug effects* / Q000502:physiology; D011187:Posture / Q000502:physiology*
chemical_list: D004958:Estradiol