title: Relationships among sleep timing, sleep duration and glycemic control in Type 2 diabetes in Thailand.
abstract: There is evidence that the sleep and circadian systems play a role in glucose metabolism. In addition to physiological factors, sleep is also affected by behavioral, environmental, cultural and social factors. In this study, we examined whether morning or evening preference, sleep timing and sleep duration are associated with glycemic control in patients with type 2 diabetes residing in Thailand. Two hundred and ten type 2 diabetes patients who were not shift workers completed an interview and questionnaires to collect information on diabetes history, habitual sleep duration and sleep timing. Chronotype, an individual's tendency for being a "morning" or "evening" person, was assessed using the Composite Score of Morningness (CSM), which reflects an individual's subjective preference for activities in the morning or evening, as well as mid-sleep time on weekend nights (MSF), which reflects their actual sleep behavior. Most recent hemoglobin A1c (HbA1c) values were retrieved from medical records. Evening preference (as indicated by lower CSM), later bedtime on weekends, and shorter sleep duration correlated with higher HbA1c (r = -0.18, p = 0.01; r = 0.17, p = 0.01 and r = -0.17, p = 0.01, respectively), while there was no association between MSF or wake up time and glycemic control. In addition, later bedtime on weekends significantly correlated with shorter sleep duration (r = -0.34, p < 0.001). Hierarchical regression analyses adjusting for age, sex, body mass index, insulin use and diabetes duration revealed that later bedtime on weekends was significantly associated with poorer glycemic control (B = 0.018, p = 0.02), while CSM was not. Mediation analysis revealed that this association was fully mediated by sleep duration. In summary, later bedtime on weekends was associated with shorter sleep duration and poorer glycemic control in patients with type 2 diabetes. It is likely that patients with later weekend bedtimes curtail their sleep by waking up earlier. Exploring the potential reasons for this phenomenon (e.g. cultural influences, metropolitan lifestyle, environmental factors, family and social obligations) specific to a Thai population may help identify behavioral modifications (i.e. earlier bedtime and/or sleep duration extension) that could possibly lead to improved glycemic control in this population.
authors.affiliation: a Section of Endocrinology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital , Mahidol University , Bangkok , Thailand .
authors.forename: Sirimon
authors.initials: S
authors.lastname: Reutrakul
authors.affiliation: a Section of Endocrinology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital , Mahidol University , Bangkok , Thailand .
authors.forename: Nantaporn
authors.initials: N
authors.lastname: Siwasaranond
authors.affiliation: a Section of Endocrinology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital , Mahidol University , Bangkok , Thailand .
authors.forename: Hataikarn
authors.initials: H
authors.lastname: Nimitphong
authors.affiliation: a Section of Endocrinology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital , Mahidol University , Bangkok , Thailand .
authors.forename: Sunee
authors.initials: S
authors.lastname: Saetung
authors.affiliation: b Division of Pulmonary and Critical Care Medicine , Department of Medicine, Faculty of Medicine, Chulalongkorn University , Bangkok , Thailand .|c Excellence Center for Sleep Disorders, King Chulalongkorn Memorial Hospital, Thai Red Cross Society , Bangkok , Thailand .
authors.forename: Naricha
authors.initials: N
authors.lastname: Chirakalwasan
authors.affiliation: a Section of Endocrinology, Department of Medicine, Faculty of Medicine Ramathibodi Hospital , Mahidol University , Bangkok , Thailand .
authors.forename: Boonsong
authors.initials: B
authors.lastname: Ongphiphadhanakul
authors.affiliation: d Section for Clinical Epidemiology and Biostatistics, Faculty of Medicine Ramathibodi Hospital , Mahidol University , Bangkok , Thailand , and.
authors.forename: Ammarin
authors.initials: A
authors.lastname: Thakkinstian
authors.affiliation: e Department of Behavioral Sciences , Rush University Medical Center , Chicago , IL , USA.
authors.forename: Megan M
authors.initials: MM
authors.lastname: Hood
authors.affiliation: e Department of Behavioral Sciences , Rush University Medical Center , Chicago , IL , USA.
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Crowley
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D005260:Female; D038321:Glycemic Index; D006801:Humans; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires; D013785:Thailand; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology*
chemical_list: D001786:Blood Glucose
keywords: Bedtime; Type 2 diabetes; chronotype; glycemic control; sleep duration