title: Relationship between sleep duration and body mass index depends on age.
abstract: OBJECTIVE
  Sleep duration is associated with obesity and cardiometabolic disease. It is unclear, though, how these relationship differs across age groups.
  
  
  METHODS
  Data from 2007 to 2008 National Health and Nutrition Examination Survey (NHANES) were used, including respondents aged 16+ with complete data (N = 5,607). Sleep duration and age were evaluated by self-report, and body mass index (BMI) was assessed objectively. Sleep duration was evaluated continuously and categorically [very short (≤4 h), short (5-6 h), and long (≥9 h) versus average (7-8 h)]. Age was also evaluated continuously and categorically [adolescent (16-17 years), young adult (18-29 years), early middle age (30-49 years), late middle age (50-64 years), and older adult (≥65 years)].
  
  
  RESULTS
  There was a significant interaction with age for both continuous (Pinteraction  = 0.014) and categorical (Pinteraction  = 0.035) sleep duration. A pseudo-linear relationship was seen among the youngest respondents, with the highest BMI associated with the shortest sleepers and the lowest BMI associated with the longest sleepers. This relationship became U-shaped in middle-age, and less of a relationship was seen among the oldest respondents.
  
  
  CONCLUSIONS
  These findings may provide insights for clinical recommendations and could help to guide mechanistic research regarding the sleep-obesity relationship.
authors.affiliation: Department of Psychiatry, University of Arizona College of Medicine, Tucson, Arizona, USA.|Behavioral Sleep Medicine Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Grandner
authors.affiliation: Behavioral Sleep Medicine Program, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Schopfer
authors.affiliation: Center for Evidence-Based Medicine, Elsevier, Inc., Philadelphia, Pennsylvania, USA.
authors.forename: Megan
authors.initials: M
authors.lastname: Sands-Lincoln
authors.affiliation: Department of Psychology, University of Southern California, Los Angeles, California, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Jackson
authors.affiliation: Division of Pulmonary, Critical Care, and Sleep Medicine, University of California, San Diego, La Jolla, California, USA.
authors.forename: Atul
authors.initials: A
authors.lastname: Malhotra
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D057566:Self Report; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000209:etiology; D013997:Time Factors; D055815:Young Adult