title: The additive impact of periodic limb movements during sleep on inflammation in patients with obstructive sleep apnea.
abstract: BACKGROUND
  Both periodic limb movements during sleep (PLMS) and obstructive sleep apnea (OSA) are major causes of sleep disorders and have been associated with systemic inflammation and cardiovascular events. However, it is uncertain whether in combination they promote a higher inflammatory response and greater risk of cardiovascular events than each condition alone.
  
  
  OBJECTIVE
  To investigate whether the presence of PLMS is associated with increased inflammation in patients suspected of having OSA.
  
  
  METHODS
  In 342 patients who underwent polysomnography to diagnose OSA, plasma C-reactive protein (CRP) and fibrinogen levels were measured.
  
  
  RESULTS
  OSA was found in 254 patients, with 46 also having PLMS. Among the 88 patients who did not have OSA, 8 had PLMS. Plasma CRP and fibrinogen levels in the group with both PLMS and OSA were higher than in patients with neither OSA nor PLMS and in patients with OSA only (CRP: 0.20 ± 0.48 vs. 0.09 ± 0.15 vs. 0.13 ± 0.18 mg/dl, P = 0.03; fibrinogen: 298.2 ± 76.1 vs. 269.0 ± 57.1 vs. 270.0 ± 52.6 mg/dl, P < 0.01). Multivariate analysis showed that the presence of PLMS was associated with higher plasma CRP levels (β = 0.1401, P < 0.01) and fibrinogen levels (β = 0.1359, P = 0.01) independently from other clinical variables such as body mass index and the severity of OSA.
  
  
  CONCLUSIONS
  PLMS were positively associated with plasma CRP and fibrinogen levels in patients suspected of having OSA. Because plasma levels of these proteins have been established as predictive factors of future cardiovascular events, the presence of PLMS may be a useful clinical sign to identify patients with OSA at high risk of cardiovascular events.
authors.affiliation: 1 Department of Respiratory Medicine, and.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Murase
authors.forename: Takefumi
authors.initials: T
authors.lastname: Hitomi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamada
authors.forename: Masanori
authors.initials: M
authors.lastname: Azuma
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Toyama
authors.forename: Yuka
authors.initials: Y
authors.lastname: Harada
authors.forename: Kiminobu
authors.initials: K
authors.lastname: Tanizawa
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Handa
authors.forename: Chikara
authors.initials: C
authors.lastname: Yoshimura
authors.forename: Toru
authors.initials: T
authors.lastname: Oga
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
authors.forename: Kazuo
authors.initials: K
authors.lastname: Chin
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000209:etiology; D016022:Case-Control Studies; D005260:Female; D005340:Fibrinogen / Q000378:metabolism*; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D020189:Nocturnal Myoclonus Syndrome / Q000097:blood / Q000150:complications* / Q000473:pathology; D017286:Polysomnography; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000150:complications* / Q000473:pathology
chemical_list: D015415:Biomarkers; D005340:Fibrinogen; D002097:C-Reactive Protein