title: Age and sex differences in cerebral hemodynamics: a transcranial Doppler study.
abstract: OBJECTIVE
  Hemodynamic factors seem to play an important role in the pathogenesis of cerebral ischemic events. The aim of this study was to evaluate whether changes in cerebrovascular reactivity occur in women after menopause.
  
  
  METHODS
  Using transcranial Doppler ultrasonography, we studied the changes of flow velocity after hypercapnia in the middle cerebral arteries of 45 healthy premenopausal women (mean age, 32.3 years; range, 20 to 47 years) and 40 postmenopausal women (mean age, 54.4 years; range, 48 to 64 years). The same measurements were recorded in two groups of healthy male subjects age matched with premenopausal (45 subjects) and postmenopausal women (40 subjects). Moreover, a subgroup of postmenopausal women aged 48 to 53 years (15 subjects) were compared with a group of 15 premenopausal women of the same age. We obtained hypercapnia with breath holding and evaluated cerebrovascular reactivity with the breath-holding index (BHI).
  
  
  RESULTS
  BHI was significantly lower in postmenopausal women (0.89+/-0.3) than in premenopausal women (1.59+/-0.3; P<0.0001) and in young (1.34+/-0.5; P<0.001) and old men (1.20+/-0.4; P<0.04). In the latter group, BHI was significantly lower than in premenopausal women (P<.0001). BHI values were also significantly lower in postmenopausal than in premenopausal women of the same age (0.81+/-0.1 versus 1.34+/-0.1; P<0.0001).
  
  
  CONCLUSIONS
  These findings suggest that the large reduction of cerebrovascular reactivity in postmenopausal women cannot be considered a simple factor related to aging but is probably influenced by hormonal changes. The alteration in cerebrovascular regulation could be involved in the increase of cerebrovascular disease in postmenopausal women.
authors.affiliation: IRCCS S. Lucia, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Matteis
authors.forename: E
authors.initials: E
authors.lastname: Troisi
authors.forename: B C
authors.initials: BC
authors.lastname: Monaldo
authors.forename: C
authors.initials: C
authors.lastname: Caltagirone
authors.forename: M
authors.initials: M
authors.lastname: Silvestrini
mesh_terms: D000328:Adult; D000367:Age Factors; D001049:Apnea / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000098:blood supply; D016022:Case-Control Studies; D002536:Cerebral Arteries / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology; D017697:Premenopause / Q000502:physiology; D012737:Sex Factors; D013997:Time Factors; D017585:Ultrasonography, Doppler, Transcranial