title: Sleep-wake cycle irregularities in type 2 diabetics.
abstract: BACKGROUND
  The incidence of type 2 diabetes mellitus (T2DM) has been increasing in recent years. Sleep loss and circadian rhythm abnormalities are thought to be one of the underlying causes of adverse metabolic health. However, little is known about sleep-wake cycle irregularities in T2DM. The present study compared the bedtime, waking time, and estimated sleep duration between T2DM and non-T2DM subjects.
  
  
  METHODS
  The study subjects were 106 consecutive outpatients with lifestyle-related diseases (males/females = 56/50), who answered a questionnaire on sleep status. Subjects were divided into two groups; non-T2DM (n = 32) and T2DM (n = 74) subjects.
  
  
  RESULTS
  T2DM subjects retired to bed on weekdays and holidays significantly later than non-T2DM subjects (23:43 versus 22:52, p = 0.0032; 23:45 versus 22:53, p = 0.0038, respectively), and woke up significantly later on weekdays and holidays, compared with non-T2DM subjects (06:39 versus 06:08, p = 0.0325; 06:58 versus 06:24, p = 0.0450, respectively). There was no significant difference in the estimated sleep duration between the two groups. Daytime sleepiness was reported significantly more commonly by T2DM subjects than non-T2DM subjects (p = 0.0195).
  
  
  CONCLUSIONS
  Sleep-wake cycle irregularities are more common in T2DM subjects than non-T2DM. Confirmation that such irregularity plays a role in the metabolic abnormalities of T2DM requires further investigation in the future.
  
  
  BACKGROUND
  UMIN 000002998.
authors.affiliation: Department of Metabolic Medicine, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan. kkishida@imed2.med.osaka-u.ac.jp.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nakanishi-Minami
authors.forename: Ken
authors.initials: K
authors.lastname: Kishida
authors.forename: Tohru
authors.initials: T
authors.lastname: Funahashi
authors.forename: Iichiro
authors.initials: I
authors.lastname: Shimomura