title: Combined effects of sleep quality and depression on quality of life in patients with type 2 diabetes.
abstract: BACKGROUND
  Poor sleep quality and depression negatively impact the health-related quality of life of patients with type 2 diabetes, but the combined effect of the two factors is unknown. This study aimed to assess the interactive effects of poor sleep quality and depression on the quality of life in patients with type 2 diabetes.
  
  
  METHODS
  Patients with type 2 diabetes (n = 944) completed the Diabetes Specificity Quality of Life scale (DSQL) and questionnaires on sleep quality and depression. The products of poor sleep quality and depression were added to the logistic regression model to evaluate their multiplicative interactions, which were expressed as the relative excess risk of interaction (RERI), the attributable proportion (AP) of interaction, and the synergy index (S).
  
  
  RESULTS
  Poor sleep quality and depressive symptoms both increased DSQL scores. The co-presence of poor sleep quality and depressive symptoms significantly reduced DSQL scores by a factor of 3.96 on biological interaction measures. The relative excess risk of interaction was 1.08. The combined effect of poor sleep quality and depressive symptoms was observed only in women.
  
  
  CONCLUSIONS
  Patients with both depressive symptoms and poor sleep quality are at an increased risk of reduction in diabetes-related quality of life, and this risk is particularly high for women due to the interaction effect. Clinicians should screen for and treat sleep difficulties and depressive symptoms in patients with type 2 diabetes.
authors.affiliation: School of Public Health, Xuzhou Medical University, Xuzhou, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Control and Prevention of Chronic Non-communicable Diseases, Xuzhou Center for Disease Control and Prevention, School of Public Health, Xuzhou Medical University, 42 West Erhuan Road, Xuzhou, Jiangsu, China. lpa82835415@126.com.
authors.forename: Peian
authors.initials: P
authors.lastname: Lou
authors.affiliation: Department of Control and Prevention of Chronic Non-communicable Diseases, Xuzhou Center for Disease Control and Prevention, Xuzhou, China.
authors.forename: Guiqiu
authors.initials: G
authors.lastname: Chang
authors.affiliation: Department of Control and Prevention of Chronic Non-communicable Diseases, Xuzhou Center for Disease Control and Prevention, Xuzhou, China.
authors.forename: Peipei
authors.initials: P
authors.lastname: Chen
authors.affiliation: Department of Control and Prevention of Chronic Non-communicable Diseases, Xuzhou Center for Disease Control and Prevention, Xuzhou, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Control and Prevention of Chronic Non-communicable Diseases, Xuzhou Center for Disease Control and Prevention, Xuzhou, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Control and Prevention of Chronic Non-communicable Diseases, Xuzhou Center for Disease Control and Prevention, Xuzhou, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Qiao
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D003863:Depression / Q000150:complications* / Q000175:diagnosis; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000523:psychology*; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D057566:Self Report; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications* / Q000175:diagnosis; D011795:Surveys and Questionnaires
keywords: Attributable proportion; Depression; Diabetes specificity quality of life scale; Interaction; Relative excess risk of interaction; Sleep quality; Synergy index; Type 2 diabetes mellitus