A Systematic Review of Studies Investigating the Impact of Sleep Quality on Metabolic Variables in Individuals With T2DM

Background This systematic review was conducted by including recent studies in the literature that examine the relationship between sleep quality and metabolic parameters in individuals with type 2 diabetes. Objectives The aim was to contribute to the literature by evaluating studies that investigate the impact of sleep quality on metabolic variables in individuals with type 2 diabetes. Methods Research indexed in international databases between 1995 and 2025 and meeting specified criteria was included. Sleep quality was assessed based on factors such as duration, continuity, sleep onset latency, and individual satisfaction with sleep. The studies were also analyzed and compared according to glycemic control variables (HbA1c levels), which are considered to be influenced by sleep. A total of 38 studies meeting the criteria were included after screening seven databases. Findings The findings indicate that insufficient and poor-quality sleep is generally associated with elevated HbA1c levels, impaired glucose tolerance, increased insulin resistance, and adverse lipid profiles. Furthermore, some studies have reported that sleep disorders may negatively affect the course of diabetes by contributing to increased inflammatory markers. Conclusion The findings suggest that sleep quality is an important lifestyle factor to consider in the management of type 2 diabetes. They also underscore the importance of healthcare professionals integrating sleep assessments and interventions into clinical practice for individuals with diabetes.