title: Midlife women's responses to a hospital sleep challenge: aging and menopause effects on sleep architecture.
abstract: OBJECTIVE
  To distinguish aging from menopause effects on sleep architecture, we studied an episode of disturbed hospital sleep in asymptomatic midlife women during the follicular phase of an ovulatory cycle and three control groups differing by age or menopause status.
  
  
  METHODS
  Fifty-one studies were conducted in four groups of volunteers: young cycling (YC, 20-30 years, n = 14), older cycling (OC, 40-50 years, n = 15), ovariectomized receiving estrogen therapy (OVX, 40-50 years, n = 12), and spontaneously postmenopausal (PM, 40-50 years, n = 10). Subjects were admitted to the University Hospital General Clinical Research Center (GCRC) for a first-night sleep study conducted during a 24-hour, frequent blood sampling protocol.
  
  
  RESULTS
  Despite similar estrogen concentrations in the YC (28 +/- 4 pg/ml) and OC (34 +/- 6 pg/ml) groups, OC women had reduced sleep efficiency (79% +/- 2%) vs. YC (87% +/- 3%; p = 0.009). In the OVX and PM groups where estrogen concentrations were markedly different, sleep efficiency was also reduced vs. the YC group (OVX vs. YC, 79% +/- 3% vs. 87% +/- 3%, p = 0.05; PM vs. YC, 75% +/- 3% vs. 87% +/- 3%, p = 0.007). Wake time was longer in the three older groups (103 +/- 10 minutes, 101 +/- 12 minutes, 123 +/- 12 minutes for OC, OVX, PM, respectively) vs. YC (63 +/- 13 minutes, p < 0.05). The number of stage shifts was positively associated with advancing age (rho = 0.3, p < 0.03) but not with estrogen concentration.
  
  
  CONCLUSIONS
  Aging-related sleep deficits in response to an experimental stressor occur in midlife women prior to menopause.
authors.affiliation: School of Nursing, General Clinical Research Center, and Reproductive Sciences Program, University of Michigan, Ann Arbor, Michigan.
authors.forename: Jane L
authors.initials: JL
authors.lastname: Lukacs
authors.forename: Julie L
authors.initials: JL
authors.lastname: Chilimigras
authors.forename: Jason R
authors.initials: JR
authors.lastname: Cannon
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Dormire
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Reame
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology; D001800:Blood Specimen Collection / Q000523:psychology; D002940:Circadian Rhythm; D015914:Estrogen Replacement Therapy; D005260:Female; D005498:Follicular Phase; D006801:Humans; D008593:Menopause; D008875:Middle Aged; D012892:Sleep Deprivation / Q000209:etiology; D020178:Sleep Disorders, Circadian Rhythm / Q000209:etiology; D012895:Sleep, REM / Q000502:physiology; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology