title: Association of short sleep duration with weight gain and obesity at 1-year follow-up: a large-scale prospective study.
abstract: OBJECTIVE
  To investigate the association between short sleep duration and elevated body mass index (BMI) and obesity in a large sample of Japanese adults over a short period.
  
  
  METHODS
  Prospective design with baseline in 2006 and 1-year follow-up.
  
  
  METHODS
  Workplaces of an electric power company in Japan.
  
  
  METHODS
  35,247 company employees (31,477 men, 3,770 women) distributed throughout Japan.
  
  
  RESULTS
  Measured weight and height and self-reported sleep duration were obtained at annual health checkup in 2006 and 2007. Weight change was defined as the difference in body mass index (BMI) between the baseline and 1 year later. Relative to the reference category (sleep duration 7-8 h), short sleep duration (< 5 and 5-6 h) and long sleep duration > or = 9 h were associated with an increased risk of weight gain among men after adjustment for covariates. Of the non-obese (BMI < 25) men at baseline, 5.8% became obese (BMI > or = 25) 1 year later. Higher incidence of obesity was observed among the groups with shorter sleep duration. Adjusted odds ratios for the development of obesity were 1.91 (95% CI 1.36, 2.67) and 1.50 (95% CI 1.24, 1.80) in men who slept < 5 and 5-6 h, respectively. No significant association between sleep duration and weight gain or obesity was found for women.
  
  
  CONCLUSIONS
  Short sleep duration was associated with weight gain and the development of obesity over 1 year in men, but not in women.
authors.affiliation: Department of Occupational Mental Health, Graduate School of Medical Sciences, Kitasato University, Sagamihara City, Japan. wmayumi-sgy@umin.net
authors.forename: Mayumi
authors.initials: M
authors.lastname: Watanabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kikuchi
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Tanaka
authors.forename: Masaya
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D000328:Adult; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D015438:Health Behavior; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007564:Japan; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D011446:Prospective Studies; D012892:Sleep Deprivation / Q000453:epidemiology*; D013223:Statistics as Topic; D015430:Weight Gain