Exploring the Relationship Between Sleep Amount and Type 1 Diabetes

Although sleep is a multifaceted aspect of health, a majority of young adults are not reaching the recommended amount of seven to nine hours of sleep each night. A lack of sleep is known to cause a multitude of health issues, including impaired glucoregulation in Type 1 diabetes (T1D). A recent study from The Journal of Clinical Endocrinology & Metabolism explored the relationship between sleep and glucose variability with the hope of uncovering modifiable sleep targets to improve glucose and glycemic control.

T1D affects more than 45 million people and is steadily rising. However, only a small percentage of young adults with T1D reach their glycemic targets (glycosylated hemoglobin A1c [HbA1c] < 7%), and higher HbA1c values are often predictors for premature micro- and macrovascular complications. It is also known that not getting enough sleep leads to impaired glucose metabolism and hormonal and body weight regulation both in individuals with and without T1D. Therefore, a better understanding of the sleep-glucose association and the sleep habits of young adults with T1D could reveal modifiable personal targets to improve glucose variability and glycemic control while reducing the risk for micro- and macrovascular complications.

Study design

The authors used multilevel models to analyze concurrent sleep and glucose patterns over one week. Data was collected from a sleep-wake activity monitor and a continuous glucose monitoring (CGM) device. A total of 42 individuals wore the devices concurrently for seven continuous days/nights. The participants ranged in age from 18 to 30 years, had been diagnosed with T1D for at least six months (mean 10.3 ± 6.1 years) and had no other major health problems. The group was also 66.7% female and were 83.3% non-Hispanic white. The mean HbA1c was 7.2% ± 1.1%, and most used an insulin pump (78.6%) and CGM (80.9%) for treatment.

In order to distinguish associations of glucose variability with a participant’s typical sleep pattern (between-person differences) from associations with prior-day sleep characteristics (within-person differences), the authors analyzed daily data from actigraphy and GCM to estimate associations in sleep and glucose patterns.

“A between-persons relationship indicated relationships among interindividual differences in sleep and glucose variables,” explains Sangeeta Kashyap, MD, one of the study’s authors and a Physician-Scientist in Cleveland Clinic’s Endocrinology & Metabolism Institute. “On the other hand, a within-person relationship between sleep and next-day glucose and vice versa indicated the existence of intraindividual variation within a person repeatedly over time. This distinction was important in illustrating how an individual varies from their own baseline data, and this is the first study in young adults with T1D where both these variations in objective sleep-wake characteristics were examined.”

Findings

The authors found that lower sleep efficiency (the ratio of time in bed to total time asleep and an indicator of sleep quality) was associated with higher glucose variability (less time in the range of β = 0.011 and more time in hyperglycemia β = −0.011) within-person. Also associated with higher glucose variability were more sleep disruptions and a longer wake after sleep onset (β = 0.31 and 0.28, respectively). Participants who exhibited higher glucose variability also exhibited poor poorer sleep within-person. This included delayed bedtime, waketime, mid-sleep time and lower sleep efficiency. The same relationship between higher glucose variability and poorer sleep was also evident between persons i.e., lower sleep efficiency, longer wake after sleep onset and a higher sleep fragmentation index.

“We found a direct correlation showing that higher sleep efficiency predicted better achievement of glucose targets,” says Dr. Kashyap. “In other words, more time spent asleep while in bed leads to higher sleep efficiency. But it is important to make the distinction that sleep efficiency should not be considered in isolation from total sleep time. Even though a person who sleeps for four hours and stays asleep the entire time would have 100% sleep efficiency, four hours is still well below the recommended amount of sleep.”

The authors believe their findings support the importance of assessing sleep as part of the routine care of young adults with T1D. “Many of the causes of poor sleep, such as bedtime, time in bed, sleep regularity, sleep efficiency, etc., are all things that be controlled by the individual,” says Dr. Kashyap. “Working with patients to help them take steps to improve sleep can have a profound effect on this population through improved diabetes self-management, waketime alertness and quality of life outcomes.”