title: Hypocretin deficiency in narcoleptic humans is associated with abdominal obesity.
abstract: OBJECTIVE
  To determine the prevalence of obesity among patients with narcolepsy, to estimate associated long-term health risks on the basis of waist circumference, and to distinguish the impact of hypocretin deficiency from that of increased daytime sleepiness (i.e., reduced physical activity) on these anthropometric measures.
  
  
  METHODS
  A cross-sectional, case-control study was conducted. Patients with narcolepsy (n = 138) or idiopathic hypersomnia (IH) (n = 33) were included. Age-matched, healthy members of the Dutch population (Monitoring Project on Risk Factors for Chronic Diseases and Doetinchem Project; n = 10,526) were used as controls. BMI and waist circumference were determined.
  
  
  RESULTS
  Obesity (BMI > or = 30 kg/m(2)) and overweight (BMI 25 to 30 kg/m(2)) occurred more often among narcolepsy patients [prevalence: 33% (narcoleptics) vs. 12.5% (controls) and 43% (narcoleptics) vs. 36% (controls), respectively; both p < 0.05]. Narcoleptics had a larger waist circumference (mean difference 5 +/- 1.4 cm, p < 0.001). The BMI of patients with IH was significantly lower than that of narcolepsy patients (25.6 +/- 3.6 vs. 28.5 +/- 5.4 kg/m(2); p = 0.004).
  
  
  CONCLUSIONS
  Overweight and obesity occur frequently in patients with narcolepsy. Moreover, these patients have an increased waist circumference, indicating excess fat storage in abdominal depots. The fact that patients with IH had a lower BMI than narcoleptics supports the notion that excessive daytime sleepiness (i.e., inactivity) cannot account for excess body fat in narcoleptic patients.
authors.affiliation: Department of General Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Simon W
authors.initials: SW
authors.lastname: Kok
authors.forename: Sebastiaan
authors.initials: S
authors.lastname: Overeem
authors.forename: Tommy L S
authors.initials: TL
authors.lastname: Visscher
authors.forename: Gert Jan
authors.initials: GJ
authors.lastname: Lammers
authors.forename: Jaap C
authors.initials: JC
authors.lastname: Seidell
authors.forename: Hanno
authors.initials: H
authors.lastname: Pijl
authors.forename: Arend E
authors.initials: AE
authors.lastname: Meinders
mesh_terms: D000005:Abdomen / Q000033:anatomy & histology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001824:Body Constitution; D015992:Body Mass Index; D002352:Carrier Proteins; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D020177:Idiopathic Hypersomnia / Q000097:blood / Q000150:complications*; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D009290:Narcolepsy / Q000097:blood / Q000150:complications*; D009479:Neuropeptides / Q000172:deficiency*; D009765:Obesity / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D000068797:Orexins; D015995:Prevalence
chemical_list: D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins