title: The impact of sleep duration in obstructive sleep apnea patients.
abstract: OBJECTIVE
  Obstructive sleep apnea (OSA) is a risk factor for cardiovascular disease. Strong associations have been reported among sleep duration, hypertension, obesity, and cardiovascular mortality. The authors hypothesize that sleep duration may play a role in OSA severity. The aim of this study is to analyze sleep duration in OSA patients.
  
  
  METHODS
  Patients who underwent overnight polysomnography were consecutively selected from the Sleep Clinic of Universidade Federal de São Paulo database between March 2009 and December 2010. All subjects were asked to come to the Sleep Clinic at 8:00 a.m. for a clinical evaluation and actigraphy. Anthropometric parameters such as weight, height, hip circumference, abdominal circumference, and neck circumference were also measured.
  
  
  RESULTS
  One hundred thirty-three patients were divided into four groups based on total sleep time, sleep efficiency, sleep latency, and wake after sleep onset: very short sleepers (n = 11), short sleepers (n = 21), intermediate sleepers (n = 56), and sufficient sleepers (n = 45). Apnea-hypopnea index (AHI) was higher in very short sleepers (50.18 ± 30.86 events/h) compared with intermediate sleepers (20.36 ± 14.68 events/h; p = 0.007) and sufficient sleepers (23.21 ± 20.45 events/h; p = 0.02). Minimal and mean arterial oxygen saturation and time spent below 90 % oxygen saturation exhibited worse values in very short sleepers. After adjustment for gender, age, AHI, and body mass index, mean oxygen saturation was significantly associated to total sleep time (p = 0.01).
  
  
  CONCLUSIONS
  In conclusion, the present study suggests that sleep duration may be associated to low mean oxygen saturation in OSA patients.
authors.affiliation: Cardiology Division, Medicine Department, Universidade Federal de São Paulo, Rua Napoleão de Barros, 925. Vila Clementino, São Paulo, SP 04024-002, Brazil. thaisrisso@yahoo.com.br
authors.forename: Thaís T
authors.initials: TT
authors.lastname: Risso
authors.forename: Dalva
authors.initials: D
authors.lastname: Poyares
authors.forename: Camila F
authors.initials: CF
authors.lastname: Rizzi
authors.forename: Cristiane
authors.initials: C
authors.lastname: Pulz
authors.forename: Christian
authors.initials: C
authors.lastname: Guilleminault
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.forename: Angelo A V
authors.initials: AA
authors.lastname: de Paola
authors.forename: Fátima
authors.initials: F
authors.lastname: Cintra
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000886:Anthropometry; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D012307:Risk Factors; D012737:Sex Factors; D012892:Sleep Deprivation; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis*; D012894:Sleep Stages
chemical_list: D010100:Oxygen