Abstract
Introduction
The association between short sleep duration and poorer glycemic control in adolescents ages 10-16 with type 1 diabetes (T1D) is well established. Researchers have used cross-sectional, between-subjects’ methods, with limited focus on the potential intraindividual variation among these variables. The purpose of this analysis was to examine the within person associations between glucose variability indices (J index, low/high blood glucose index, time in range) and sleep characteristics (bedtime, waketime, total sleep time, sleep efficiency, wake after sleep onset [WASO], awakenings, and sleep fragmentation index) in adolescents with T1D.
Methods
Adolescents monitored their sleep and glucose patterns concurrently for 3-7 days with a wrist actigraph on their non-dominant wrist and either their own continuous glucose monitor (CGM) or a provided blinded CGM. General linear mixed models (GLMM) were used to determine within-person and day level associations.
Results
The sample included 38 adolescents (M age 13.4±1.8; 37.8% male; M A1C 8.2±1.2%). Average glucose levels were controlled in all GLMMs. Adolescents had earlier waketimes on days when more time was spent in hypoglycemia <70mg/dL (β=-0.15, p<0.001). At the person level, adolescents had greater WASO with more % time spent in severe hypoglycemia <54mg/dL with more severe low blood glucose indices (β=0.35, p<0.01 and β=0.34, p<0.01 respectively). At the daily level, adolescents had greater WASO (β=0.20, p=0.01) and more awakenings (β=0.16, p=0.04) on the days they had more overall glucose variability (J index) and more severe high blood glucose indices (β=0.17, p=0.04), but were less likely to have more % time in hypoglycemia (β=-0.15, p=0.02).
Conclusion
Glucose variability was positively associated with poor sleep (e.g., WASO and awakenings) in adolescents with T1D both at the daily and intraindividual level. Monitoring over a longer period of time in subsequent studies would allow researchers to determine the within person associations between habitual short sleep duration and glucose variability.
Support
NINR T32NR0008346 & P20NR014126, Medtronic MiniMed provided CGMs at a discounted rate for the study.
Association of morning fasting blood glucose variability with insulin antibodies and clinical factors in type 1 diabetes