title: Relationship between sleep characteristics and measures of body size and composition in a nationally-representative sample.
abstract: BACKGROUND
  Short sleep has been linked to obesity. However, sleep is a multidimensional behavior that cannot be characterized solely by sleep duration. There is limited study that comprehensively examined different sleep characteristics in relation to obesity.
  
  
  METHODS
  We examined various aspects of sleep in relation to adiposity in 2005-2006 NHANES participants who were 18 or older and free of cardiovascular disease, cancer, emphysema, chronic bronchitis and depression (N= 3995). Sleep characteristics were self-reported, and included duration, overall quality, onset latency, fragmentation, daytime sleepiness, snoring, and sleep disorders. Body measurements included weight, height, waist circumference, and dual-energy X-ray absorptiometry measured fat mass.
  
  
  RESULTS
  Snoring was associated with higher BMI (adjusted difference in kg/m2comparing snoring for 5+ nights/week with no snoring (95 % confidence interval), 1.85 (0.88, 2.83)), larger waist circumference (cm, 4.52 (2.29, 6.75)), higher percentage of body fat (%, 1.61 (0.84, 2.38)), and higher android/gynoid ratio (0.03 (0.01, 0.06)). The associations were independent of sleep duration and sleep quality, and cannot be explained by the existence of sleep disorders such as sleep apnea. Poor sleep quality (two or more problematic sleep conditions) and short sleep duration (<6 h) were also associated with higher measures of body size and fat composition, although the effects were attenuated after snoring was adjusted.
  
  
  CONCLUSIONS
  In a nationally representative sample of healthy US adults, snoring, short sleep, and poor sleep quality were associated with higher adiposity.
authors.affiliation: Department of Health and Human Physiology, University of Iowa, E118 Field House, Iowa City, Iowa 52242 USA.
authors.forename: Qian
authors.identifier: 0000-0002-8388-1178
authors.initials: Q
authors.lastname: Xiao
authors.affiliation: Genetic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland USA.
authors.forename: Fangyi
authors.initials: F
authors.lastname: Gu
authors.affiliation: Genetic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Caporaso
authors.affiliation: Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, Maryland USA.
authors.forename: Charles E
authors.initials: CE
authors.lastname: Matthews
keywords: Body composition; Sleep duration; Sleep quality; Snoring