title: Association of napping and night-time sleep with impaired glucose regulation, insulin resistance and glycated haemoglobin in Chinese middle-aged adults with no diabetes: a cross-sectional study.
abstract: OBJECTIVE
  To assess associations between napping and night-time sleep duration with impaired glucose regulation, insulin resistance (IR) and glycated haemoglobin (HbA1c).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Fujian Province, China, from June 2011 to January 2012.
  
  
  METHODS
  This study enrolled 9028 participants aged 40-65 years. Data of 7568 participants with no diabetes were included for analysis. Type 2 diabetes was defined applying WHO criteria.
  
  
  METHODS
  Participants' daytime napping and night-time sleep duration data were collected using a standardised self-reported Chinese-language questionnaire about sleep frequency and quality. Anthropometric and laboratory parameters were also measured. IR was defined as a HOMA-IR index value >2.50. ORs and 95% CIs were derived from multivariate logistic regression models.
  
  
  RESULTS
  Participants (mean age 51.1±7.0 years) included 3060 males and 4508 females with average night-time sleep of 7.9 h. A higher proportion of males napped than females. After adjustment for potential confounders, ORs for HbA1c >6.0% were 1.28 and 1.26 for those napping ≤1 h and >1 h (p=0.002 and p=0.018), respectively. Statistically significant differences in IR between nappers and non-nappers were only marginal clinically. Odds for HbA1c >6.0% were significantly lower in participants with longer night-time sleep durations than in the reference group (>8 h vs 6-8 h). Odds for IR were significantly lower in participants whose night-time sleep hours deviated from the reference group (<6 h, >8 h vs 6-8 h)
  
  
  CONCLUSIONS
  Chinese middle-aged adults with no diabetes who napped had higher HbA1c and IR; those with shorter night-time sleep durations had increased HbA1c. Night-time sleep hours that are either <6 or >8 tend to be associated with lower odds for IR. Further studies are necessary to determine the underlying clinical significance and mechanisms behind these associations.
authors: Department of Endocrinology, Ningde Municipal Hospital, Fujian Medical University, Ningde, China.
authors: Huang
authors: H
authors: Baoying
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Chen
authors: C
authors: Hongjie
authors: Department of Osteology, Wuyishan Municipal Hospital, Fujian Provincial Hospital, Wuyishan, China.
authors: Qiu
authors: Q
authors: Changsheng
authors: Department of Endocrinology, Ningde Municipal Hospital, Fujian Medical University, Ningde, China.
authors: Wu
authors: W
authors: Peijian
authors: Department of Osteology, Wuyishan Municipal Hospital, Fujian Provincial Hospital, Wuyishan, China.
authors: Lin
authors: L
authors: Qingfei
authors: Department of Endocrinology, Ningde Municipal Hospital, Fujian Medical University, Ningde, China.
authors: Lin
authors: L
authors: Yinghua
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Huang
authors: H
authors: Huibin
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Liang
authors: L
authors: Jixing
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Li
authors: L
authors: Liantao
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Chen
authors: C
authors: Ling
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Tang
authors: T
authors: Kaka
authors: Department of Endocrinology, Ningde Municipal Hospital, Fujian Medical University, Ningde, China.
authors: Chen
authors: C
authors: Zichun
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Lin
authors: L
authors: Lixiang
authors: Department of Endocrinology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Lu
authors: L
authors: Jieli
authors: Department of Endocrinology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Bi
authors: B
authors: Yufang
authors: Department of Endocrinology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Ning
authors: N
authors: Guang
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Zhu
authors: Z
authors: Penli
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Wen
authors: W
authors: Junping
authors: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, China.
authors: Chen
authors: C
authors: Gang
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D002681:China / Q000453:epidemiology; D002940:Circadian Rhythm; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications* / Q000453:epidemiology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D015994:Incidence; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin
keywords: SLEEP MEDICINE