title: Curvilinear associations of sleep patterns during weekdays and weekends with glycemic control in type 2 diabetes: the Hong Kong Diabetes Registry.
abstract: OBJECTIVE
  We aimed to explore the associations of sleep patterns during weekdays and weekends with glycemic control in patients with type 2 diabetes.
  
  
  METHODS
  We examined the association between indices of glycemic control [glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG)] and sleep parameters (sleep duration, bedtime, and differences of sleep duration during weekdays and weekends) from adults with type 2 diabetes recruited in a prospective cohort enrolling from hospital medical clinics. Restricted cubic spline regression was used to examine the relationships between the glycemic indices and sleep parameters.
  
  
  RESULTS
  Excluding shift workers, a total of 3508 patients enrolled between July 2010 and July 2014 were included in this analysis. Mean age was 53.9 [standard deviation (SD) 8.7] years, and mean disease duration of diabetes was 8.3 (SD 7.1) years. Fifty-nine percentage were men. Mean sleep duration during weekdays and difference of sleep durations between weekdays and weekends were 7.7 (SD 1.3) hours and 0.6 (SD 1.2) hours, respectively. Mean HbA1cand FPG were 7.6 (1.5) % and 7.6 (2.5) mmol/L, respectively. Using restricted cubic spline regressions with successive adjustments of potential confounders, sleep duration difference between weekdays and weekends remained significantly associated with both HbA1cand FPG in a curvilinear manner. Sleep duration of about 1 h more during weekends when compared to weekdays was associated with beneficial effect in HbA1c(-0.13 %, 95 % confidence interval -0.24 to -0.02).
  
  
  CONCLUSIONS
  In type 2 diabetes, regular sleeping habit with modest sleep compensation during weekends has positive impact on glycemic control.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong SAR, China. alicekong@cuhk.edu.hk.|Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China. alicekong@cuhk.edu.hk.|Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China. alicekong@cuhk.edu.hk.
authors.forename: Alice P S
authors.initials: AP
authors.lastname: Kong
authors.affiliation: Nethersole School of Nursing, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors.forename: Kai Chow
authors.initials: KC
authors.lastname: Choi
authors.affiliation: Department of Psychiatry, The Chinese University of Hong Kong, Shatin Hospital, Shatin, Hong Kong SAR, China.
authors.forename: Jihui
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong SAR, China.|Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.|Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
authors.forename: Andrea
authors.initials: A
authors.lastname: Luk
authors.affiliation: Department of Psychiatry, The Chinese University of Hong Kong, Shatin Hospital, Shatin, Hong Kong SAR, China.
authors.forename: Siu Ping
authors.initials: SP
authors.lastname: Lam
authors.affiliation: Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
authors.forename: Michael H M
authors.initials: MH
authors.lastname: Chan
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong SAR, China.|Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.|Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
authors.forename: Ronald C W
authors.initials: RC
authors.lastname: Ma
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, N.T., Hong Kong SAR, China.|Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.|Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.|Asia Diabetes Foundation, Shatin, Hong Kong SAR, China.
authors.forename: Juliana C N
authors.initials: JC
authors.lastname: Chan
authors.affiliation: Department of Psychiatry, The Chinese University of Hong Kong, Shatin Hospital, Shatin, Hong Kong SAR, China.
authors.forename: Yun Kwok
authors.initials: YK
authors.lastname: Wing
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis*; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005260:Female; D006723:Hong Kong; D006801:Humans; D008297:Male; D008875:Middle Aged; D017440:Photoperiod; D012042:Registries; D012890:Sleep
chemical_list: D001786:Blood Glucose
keywords: Sleep; Type 2 diabetes; Weekdays; Weekends