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

Sleep Med. 2013 Oct;14(10):950-4. doi: 10.1016/j.sleep.2013.04.015. Epub 2013 Jul 3.


Objectives: 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.

Keywords: Cross-sectional study; Diabetes mellitus; Elderly; Habitual afternoon napping; Impaired fasting plasma glucose; Risk factor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Asian People / statistics & numerical data*
  • Blood Glucose / metabolism*
  • Circadian Rhythm / physiology*
  • Cohort Studies
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Diabetes Mellitus, Type 2 / metabolism*
  • Fasting
  • Female
  • Humans
  • Hyperglycemia / epidemiology
  • Hyperglycemia / metabolism
  • Male
  • Middle Aged
  • Prevalence
  • Retirement
  • Risk Factors
  • Sleep / physiology*


  • Blood Glucose