Background: People with type 1 diabetes (T1D) often experience problems with their glucose regulation (glucose variability and glucose control), sleep quality, and cognitive functioning. However,...Show moreBackground: People with type 1 diabetes (T1D) often experience problems with their glucose regulation (glucose variability and glucose control), sleep quality, and cognitive functioning. However, their interrelation has not often been investigated. The aim of this study was to investigate how sleep quality and cognitive functioning are associated with glucose regulation in people with T1D. Method: Continuous glucose monitoring (CGM) data was collected over two weeks, in 18 participants, while each day subjective sleep quality (once in the morning) and cognitive functioning (e.g., ability to concentrate, finding words) (up to five times during the day) was measured using ecological momentary assessments (EMAs). Based on the CGM data, glycemic parameters (glucose variability and glucose control) during the night and day were calculated and a mean value of cognitive functioning per day was composed. Linear mixed model analyses were used to test for 1) whether sleep quality was influenced by glycemic parameters during the night and 2) whether cognitive functioning during the day was influenced by sleep quality and whether cognitive functioning was associated with glycemic parameters during the day. In addition, an interaction effect between sleep quality and glucose variability on cognitive functioning was explored. Lastly, visual plots were used to explore the associations on an individual level. Results: No statistically significant main effects were found for either association. However, an interaction trend (ß = -2.07, p = .070) between sleep quality and glucose variability on cognitive functioning scores was found. For days with normal fluctuations in glucose levels, better sleep quality was associated with better cognitive functioning, whereas for days with high glucose variability, this association could not be found. Regarding the individual plots, both, positive and negative relationships between all mentioned variables were apparent, exemplifying important inter-individual differences. Conclusion: For people with T1D, the relationships between glucose parameters, sleep quality, and cognitive functioning, vary from person to person. This finding advocates for looking at the individual level when implementing possible treatment methods for increasing sleep quality and cognitive functioning. More research in a larger sample is warranted to further examine the inter-individual factors in these associations.Show less