title: Night time sleep macrostructure is altered in otherwise healthy 10-year-old overweight children.
abstract: OBJECTIVE
  Epidemiological evidence shows an inverse relationship between sleep duration and overweight/obesity risk. However, there are few polysomnographic studies that relate the organization of sleep stages to pediatric overweight (OW). We compared sleep organization in otherwise healthy OW and normal-weight (NW) 10-year-old children.
  
  
  METHODS
  Polysomnographic assessments were performed in 37 NW and 59 OW children drawn from a longitudinal study beginning in infancy. Weight and height were used to evaluate body mass index (BMI) according to international criteria. Non-rapid eye movement (NREM) sleep (stages N1, N2 and N3), rapid eye movement (REM) sleep (stage R) and wakefulness (stage W) were visually scored. Sleep parameters were compared in NW and OW groups for the whole sleep period time (SPT) and for each successive third of it using independent Student's t-tests or nonparametric tests. The relationship between BMI and sleep variables was evaluated by correlation analyses controlling for relevant covariates.
  
  
  RESULTS
  The groups were similar in timing of sleep onset and offset, and sleep period time. BMI was inversely related to total sleep time (TST) and sleep efficiency. OW children showed reduced TST, sleep efficiency and stage R amount, but higher stage W amount. In analysis by thirds of the SPT, the duration of stage N3 episodes was shorter in the first third and longer in the second third in OW children as compared with NW children.
  
  
  CONCLUSIONS
  Our results show reduced sleep amount and quality in otherwise healthy OW children. The lower stage R amount and changes involving stage N3 throughout the night suggest that OW in childhood is associated with modifications not only in sleep duration, but also in the ongoing night time patterns of NREM sleep and REM sleep stages.
authors.affiliation: Sleep Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile.
authors.forename: R
authors.initials: R
authors.lastname: Chamorro
authors.affiliation: Sleep Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile.
authors.forename: C
authors.initials: C
authors.lastname: Algarín
authors.affiliation: Sleep Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile.
authors.forename: M
authors.initials: M
authors.lastname: Garrido
authors.affiliation: Electrical Engineering Department, University of Chile, Santiago, Chile.
authors.forename: L
authors.initials: L
authors.lastname: Causa
authors.affiliation: Electrical Engineering Department, University of Chile, Santiago, Chile.
authors.forename: C
authors.initials: C
authors.lastname: Held
authors.affiliation: Center for Human Growth and Development and Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA.
authors.forename: B
authors.initials: B
authors.lastname: Lozoff
authors.affiliation: Sleep Laboratory, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile.
authors.forename: P
authors.initials: P
authors.lastname: Peirano
mesh_terms: D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D050177:Overweight / Q000150:complications / Q000503:physiopathology*; D017286:Polysomnography; D012307:Risk Factors; D012890:Sleep; D012894:Sleep Stages; D014851:Wakefulness