title: Sleep-disordered breathing as a risk factor for cerebrovascular disease: a case-control study in patients with transient ischemic attacks.
abstract: OBJECTIVE
  The evidence that obstructive sleep apnea/hypopnea (OSAH) is a risk factor for ischemic cerebrovascular disease is inconclusive. We explored this relationship in transient ischemic attack (TIA) patients because they are less likely than stroke patients to have OSAH as a consequence of cerebrovascular disease.
  
  
  METHODS
  We performed a case-control study among 86 patients with TIA from a hospital neurovascular clinic, matched for age (+/-5 years) and sex with controls from the referring local family practice registers.
  
  
  RESULTS
  Forty-nine of the 86 matched pairs were male and the body mass index was similar among cases and controls. The primary outcome measure, the apnea/hypopnea index [AHI=number of (apneas+hypopneas)/h slept, measured during overnight polysomnography and scored blind to case-control status], was the same for cases and controls (21/hour). However, the median number of 4% desaturations during sleep was slightly greater in the cases (12/hour) than controls (6/hour, P=0.04). There were the expected associations between TIA and higher fibrinogen levels (TIA 3.3, control 3.0 g/L, P=0.01), previous myocardial infarction (TIA 22, control 6%, P=0.007), a history of ever smoking (TIA 71, control 54%, P=0.01), hypertension (TIA 51, control 21%, P=0.001), and raised cholesterol (TIA 27, control 10%, P=0.01), with a weak trend for diabetes mellitus (TIA 10, control 6%, P=0.4).
  
  
  CONCLUSIONS
  OSAH does not appear to be strongly associated with TIAs.
authors.affiliation: Department of Medicine, University of Edinburgh, Royal Infirmary, Edinburgh, UK.
authors.forename: Nigel
authors.initials: N
authors.lastname: McArdle
authors.forename: Renata L
authors.initials: RL
authors.lastname: Riha
authors.forename: Marjorie
authors.initials: M
authors.lastname: Vennelle
authors.forename: Emma L
authors.initials: EL
authors.lastname: Coleman
authors.forename: Martin S
authors.initials: MS
authors.lastname: Dennis
authors.forename: Charles P
authors.initials: CP
authors.lastname: Warlow
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Douglas
mesh_terms: D000368:Aged; D015992:Body Mass Index; D016022:Case-Control Studies; D002561:Cerebrovascular Disorders / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D002546:Ischemic Attack, Transient / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D017286:Polysomnography; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000175:diagnosis* / Q000453:epidemiology*; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D005340:Fibrinogen