title: Longer habitual afternoon napping is associated with a higher risk for impaired fasting plasma glucose and diabetes mellitus in older adults: results from the Dongfeng-Tongji cohort of retired workers.
abstract: OBJECTIVE
  Afternoon napping is a common habit in China. We used data obtained from the Dongfeng-Tongji cohort to examine if duration of habitual afternoon napping was associated with risks for impaired fasting plasma glucose (IFG) and diabetes mellitus (DM) in a Chinese elderly population.
  
  
  METHODS
  A total of 27,009 participants underwent a physical examination, laboratory tests, and face-to-face interview. They were categorized into four groups according to nap duration (no napping, <30, 30 to <60, 60 to <90, and > or =90 min). Logistic regression models were used to examine the odds ratios (ORs) of napping duration with IFG and DM.
  
  
  RESULTS
  Of the participants, 18,515 (68.6%) reported regularly taking afternoon naps. Those with longer nap duration had considerably higher prevalence of IFG and DM. Napping duration was associated in a dose-dependent manner with IFG and DM (P<.001). After adjusting for possible confounders, longer nap duration (>60 min; all P<.05) was still significantly associated with increased risk for IFG, and longer nap duration (>30 min) was associated with increased risk for DM; however, this finding was not significant in the group with a nap duration of 60-90 min.
  
  
  CONCLUSIONS
  Longer habitual afternoon napping was associated with a moderate increase for DM risk, independent of several covariates. This finding suggests that longer nap duration may represent a novel risk factor for DM and higher blood glucose levels.
authors.affiliation: Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, China; Department of Maternal and Child Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Fang
authors.forename: Zhongliang
authors.initials: Z
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Wu
authors.forename: Zhongqiang
authors.initials: Z
authors.lastname: Cao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liang
authors.forename: Handong
authors.initials: H
authors.lastname: Yang
authors.forename: Youjie
authors.initials: Y
authors.lastname: Wang
authors.forename: Tangchun
authors.initials: T
authors.lastname: Wu
mesh_terms: D000368:Aged; D044466:Asian People / Q000706:statistics & numerical data*; D001786:Blood Glucose / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000378:metabolism*; D005215:Fasting; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000453:epidemiology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012179:Retirement; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*
chemical_list: D001786:Blood Glucose
keywords: Cross-sectional study; Diabetes mellitus; Elderly; Habitual afternoon napping; Impaired fasting plasma glucose; Risk factor