title: [Meta-analysis of prospective cohort studies about sleep duration and risk of weight gain and obesity in adults].
abstract: OBJECTIVE
  This meta-analysis was conducted to quantitatively estimate the associations between sleep duration and weight gain or obesity in adults according to the literature retrieval results of related prospective cohort studies published before October 2014.
  
  
  METHODS
  The literature retrieval was conducted by using PubMed, Embase, Cochrane Library and Chinese databases, including CNKI, VIP and Wan Fang. The pooled relative risk (RR) and 95% confidence intervals (CI) were estimated, and the tests of the publication bias and the heterogeneity were also performed.
  
  
  RESULTS
  Sixteen literatures met the inclusion criteria were selected for analysis. In 285,452 adults surveyed in these studies, both short sleep duration and long sleep duration significantly increased the risk of weight gain (RR=1.26, 95% CI: 1.12-1.42; RR=1.12, 95% CI: 1.04-1.20), and short sleep duration also increased the risk of obesity (RR=1.35, 95% CI: 1.22-1.50, P<0.001), but long sleep duration was not associated with obesity. In subgroup analysis, the associations were stronger in the studies with higher quality and using <6 h and ≥8 h as the criteria to identify short and long sleep durations.
  
  
  CONCLUSIONS
  The meta-analysis indicated that both short and long sleep durations were associated with weight gain, and short sleep duration could also increase the risk of obesity. Therefore, public health efforts in promoting sufficient sleep may be important in the prevention of obesity.
authors.affiliation: Department of Epidemiology and Biostatistics, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology and Biostatistics, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China.
authors.forename: Lian
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Epidemiology and Biostatistics, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China.
authors.forename: Yubei
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Epidemiology and Biostatistics, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China; Email: chenkexin@tjmuch.edu.com.
authors.forename: Kexin
authors.initials: K
authors.lastname: Chen
mesh_terms: D000328:Adult; D016208:Databases, Factual; D006801:Humans; D009765:Obesity / Q000453:epidemiology*; D011446:Prospective Studies; D012306:Risk; D012890:Sleep; D013997:Time Factors; D015430:Weight Gain