title: Urine levels of catecholamines in Greek children with obstructive sleep-disordered breathing.
abstract: BACKGROUND
  Adults with obstructive sleep apnea have increased sympathetic activity. It was hypothesized that in children with symptoms of obstructive sleep-disordered breathing (SDB), morning urine levels of catecholamines correlate with severity of nocturnal hypoxemia.
  
  
  METHODS
  Children with snoring referred for polysomnography and controls without snoring were recruited. Morning urine norepinephrine, epinephrine, normetanephrine, and metanephrine levels were measured (ng/mg urine creatinine).
  
  
  RESULTS
  Twelve children (age 5.2 +/- 2.3 years) with severe hypoxemia (oxygen saturation of hemoglobin-SpO2 nadir < or =86%), 20 subjects (age 6.1 +/- 2.1 years) with moderate hypoxemia (SpO2 nadir < or =90% and >86%), 22 children (age 6.6 +/- 1.5 years) with mild nocturnal hypoxemia (SpO2 nadir >90%), and 10 controls (age 7.1 +/- 2.8 years) were studied. Children with severe hypoxemia had significantly higher log-transformed norepinephrine levels (1.63 +/- 0.29) compared to those with moderate hypoxemia (1.43 +/- 0.22; P < 0.05) or compared to controls (1.39 +/- 0.31; P < 0.05). In subjects with SDB, log-transformed oxygen desaturation of hemoglobin index or SpO2 nadir predicted log-transformed norepinephrine levels after adjustment by age, gender and body mass index (r2 = 0.24; and r2 = 0.24, respectively; P < 0.01).
  
  
  CONCLUSIONS
  Severity of nocturnal hypoxemia in children with intermittent upper airway obstruction during sleep correlates with morning urine levels of norepinephrine suggesting increased sympathetic tone.
authors.affiliation: Sleep Disorders Laboratory, University of Thessaly School of Medicine, Larissa University Hospital, Larissa, Greece. kaditia@hotmail.com
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Kaditis
authors.forename: Emmanouel I
authors.initials: EI
authors.lastname: Alexopoulos
authors.forename: Eleni
authors.initials: E
authors.lastname: Damani
authors.forename: Fotini
authors.initials: F
authors.lastname: Hatzi
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Chaidas
authors.forename: Thomais
authors.initials: T
authors.lastname: Kostopoulou
authors.forename: Arhontia
authors.initials: A
authors.lastname: Tzigeroglou
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Gourgoulianis
mesh_terms: D002395:Catecholamines / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006115:Greece; D006801:Humans; D000860:Hypoxia / Q000652:urine*; D008297:Male; D008771:Nordefrin / Q000652:urine*; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000652:urine*
chemical_list: D002395:Catecholamines; D008771:Nordefrin