title: Variation of C-reactive protein levels in adolescents: association with sleep-disordered breathing and sleep duration.
abstract: BACKGROUND
  There is increasing evidence that sleep-disordered breathing (SDB) is an independent risk factor for cardiovascular disease (CVD) in adults. C-reactive protein (CRP), a marker of systemic inflammation, is an important predictor of future cardiovascular events. The goal of this study was to quantify the associations of SDB, sleep duration, and CRP in adolescents to better understand the role of SDB in CVD risk.
  
  
  RESULTS
  Adolescents (n=143; age, 13 to 18 years; 36% black; 50% female) with a wide range of SDB severity underwent polysomnography and measurement of high-sensitivity CRP. SDB was quantified with the apnea hypopnea index (AHI) and oxygen desaturation measures. Sleep duration was estimated from 7-day actigraphy. The independent and dose-response associations of SDB with CRP were addressed through linear mixed-effects models. Forty-eight percent were overweight or obese, and 12% had SDB (AHI > or =5). CRP levels varied with increasing body mass index and SDB. After adjustment for body mass index , age, sex, and race, mean CRP levels were 0.50, 0.43, 0.97, and 1.66 mg/L for SDB severity levels of AHI <1, 1 to 4.9, 5 to 14.9, and > or =15, respectively (P=0.0049, AHI > or =15 versus <1). Adjusted mean CRP levels demonstrated a dose response with SDB above a threshold AHI of 5. This association was partially explained by overnight hypoxemia and less so by sleep duration.
  
  
  CONCLUSIONS
  In adolescents free of known CVD, an AHI > or =5 is associated with increasing levels of CRP, suggesting that pediatric SDB may confer additional CVD risk beyond that of obesity.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Medicine, Case Western Reserve University, Triangle Building Suite 260, 10400 Euclid Ave, Cleveland, OH 44106, USA. emma.larkin@case.edu
authors.forename: Emma K
authors.initials: EK
authors.lastname: Larkin
authors.forename: Carol L
authors.initials: CL
authors.lastname: Rosen
authors.forename: H Lester
authors.initials: HL
authors.lastname: Kirchner
authors.forename: Amy
authors.initials: A
authors.lastname: Storfer-Isser
authors.forename: Judith L
authors.initials: JL
authors.lastname: Emancipator
authors.forename: Nathan L
authors.initials: NL
authors.lastname: Johnson
authors.forename: Anna Marie V
authors.initials: AM
authors.lastname: Zambito
authors.forename: Russell P
authors.initials: RP
authors.lastname: Tracy
authors.forename: Nancy S
authors.initials: NS
authors.lastname: Jenny
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D001835:Body Weight; D002097:C-Reactive Protein / Q000032:analysis*; D002318:Cardiovascular Diseases / Q000209:etiology; D005260:Female; D006801:Humans; D000860:Hypoxia; D008297:Male; D009765:Obesity; D017286:Polysomnography; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000097:blood*; D012892:Sleep Deprivation; D013997:Time Factors
chemical_list: D002097:C-Reactive Protein