Multidimensional sleep health in type 2 diabetes: The role of sleep variability in glycemic control.

INTRODUCTION: Sleep health consists of multiple dimensions, which may contribute differently to glycemic control in persons with type 2 diabetes (T2D). This study evaluated the associations between sleep dimensions and glycemic control in T2D. MATERIAL AND METHODS: Seventy-five participants with T2D were enrolled. Sleep duration, efficiency, sleep midpoint, and sleep variability (standard deviation, SD, of sleep duration) were obtained from 14-day actigraphy recordings. Sleep satisfaction and daytime sleepiness (Epworth Sleepiness Scale, ESS) were obtained from questionnaires. Multidimensional sleep health score (MSH) was created from a sum of "good" sleep scores in each dimension. Hemoglobin A1C (A1C) was obtained. A stepwise regression analysis was performed to investigate independent association(s) between sleep and A1C (natural log transformed). RESULTS: Participants' mean (SD) age was 54.0 (6.0) years, median (IQR) A1C was 7.6 (6.6, 8.7)% and 57.3 % were using insulin. The mean sleep duration was 6.2 (1.0) hours, median sleep efficiency was 82.2 (77.1, 86.8)%, median sleep midpoint was 03:17 (02:32, 04:10) AM, and median SD of sleep duration was 1.15 (0.92, 1.49) hours. The median ESS was 7 (4,10). The median MSH score was 4 (3, 4). A stepwise regression analysis with additional assessment for potential confounders demonstrated that sleep variability was positive and independently associated with A1C (B = 0.116, p = 0.006; both variables ln transformed), while other sleep dimensions and MSH score were not related to A1C. CONCLUSION: Among sleep dimensions, greater variability of sleep duration may have a negative impact on glycemic control in this study. Enhancing regularity of sleep duration could potentially benefit glycemic control in T2D.