title: Increased systemic inflammation overnight correlates with insulin resistance among children evaluated for obstructive sleep apnea.
abstract: OBJECTIVE
  Obstructive sleep apnea (OSA) in children is associated with obesity, insulin resistance, and elevated baseline inflammation as measured by high-sensitivity C-reactive protein (hsCRP). Our goal was to evaluate whether inflammation increases overnight among children suspected of having OSA and to determine whether worsened inflammation is associated with the degree of OSA severity, obesity, and/or insulin resistance.
  
  
  METHODS
  Twenty-three children with clinical suspicion of OSA underwent a sleep study. Levels of hsCRP were tested the evening before and morning after the sleep study. Fasting insulin and glucose levels were measured from which the homeostasis model of insulin resistance (HOMA-IR) was calculated. Linear correlations were performed to evaluate relationships between hsCRP levels at baseline and change overnight (ΔhsCRP) vs. HOMA-IR, body mass index (BMI) z-score, and sleep study parameters related to O(2) saturation and the apnea-hypopnea index (AHI).
  
  
  RESULTS
  Among children with OSA and the entire cohort, hsCRP values were correlated with HOMA-IR and BMI z-scores. HOMA-IR but not BMI z-score correlated with ΔhsCRP overnight in the entire cohort. Sleep study parameters, including AHI mean O(2) saturation overnight, REM O(2) nadir, and non-REM O(2) nadir were not correlated with hsCRP or ΔhsCRP overnight.
  
  
  CONCLUSIONS
  Among children being evaluated for OSA, degree of insulin resistance may be an important determinant of increased systemic inflammation overnight. Sleep study markers did not correlate with ΔhsCRP, leaving uncertain the role of OSA in increasing inflammation overnight. Further studies are needed to explore these associations and their potential mechanisms.
authors.affiliation: Division of Pediatric Endocrinology, P.O. Box 800386, Charlottesville, VA 22908, USA. deboer@virginia.edu
authors.forename: Mark D
authors.initials: MD
authors.lastname: Deboer
authors.forename: James P
authors.initials: JP
authors.lastname: Mendoza
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Gabriele
authors.initials: G
authors.lastname: Ford
authors.forename: Pearl L
authors.initials: PL
authors.lastname: Yu
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Gaston
mesh_terms: D000293:Adolescent; D002097:C-Reactive Protein / Q000378:metabolism; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D009765:Obesity / Q000097:blood; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000175:diagnosis*; D013223:Statistics as Topic; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D055815:Young Adult
chemical_list: D018836:Inflammation Mediators; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein; D010100:Oxygen