Chronotype and well-being in adults with established type 2 diabetes: A cross-sectional study

Aims: ‘Chronotype’ describes an individual's sleep–wake schedule, and can be classified into morning, intermediate or evening types. Evening chronotype has been widely associated with increased cardiometabolic risk and mortality in people with type 2 diabetes. We explored associations between chronotype and markers of well-being in people with type 2 diabetes. Methods: Participants of the ‘Chronotype of Patients with Type 2 Diabetes and Effect on Glycaemic Control’ (CODEC) observational study completed questionnaires to determine chronotype (Morningness–Eveningness Questionnaire, MEQ) and concurrent measures of well-being (Diabetes-related Distress scale, Patient Health Questionnaire-9 to measure depression, and Self-Compassion Scale), as a secondary endpoint of the study. Adjusted generalised linear models were used to compare well-being between chronotype subgroups in this cohort. Results: Of the 808 individuals included in the CODEC study, from convenience sampling, 476 individuals completed the psychosocial questionnaire substudy. Of these, 67% (n = 321) were male, and 86% (n = 408) were white European. From the MEQ, 24% (n = 114) were morning chronotype, 24% (n = 113) were evening and 52% (n = 249) were intermediate chronotype. Diabetes-related distress was significantly higher in evening chronotypes (exponentiated adjusted coefficient = 1.18 (CI: 1.05–1.32)), compared to morning (padjusted = 0.005) and intermediate chronotypes (padjusted = 0.039). Similarly, depression was significantly higher in evening chronotypes (exponentiated adjusted coefficient = 1.84 (CI: 1.28–2.65)) compared to morning (padjusted = 0.001) and intermediate chronotypes (padjusted = 0.016). Discussion: Evening chronotype in people with type 2 diabetes may be associated with higher levels of diabetes-related distress and depression. These findings warrant further investigation to establish causality and evidence-based interventions that negate the effects of evening chronotype in people with type 2 diabetes.