Sleep may be an important modifiable factor in disease management in patients with type 2 diabetes (T2D), especially variation in sleep duration, according to study results published in Diabetes Care.
Sleep is known to be associated with glycemic control in T2D, but the degree to which specific sleep characteristics affect diabetes management is uncertain. Researchers conducted a cross-sectional study of patients with T2D receiving care in the Amsterdam University Medical Center system in The Netherlands to assess how sleep measures, both alone and in combination, affect glycated hemoglobin (HbA1c).
Patients wore a wrist accelerometer continuously for 1 week and the resulting data were used to algorithmically calculate total sleep duration, variability in sleep duration, sleep efﬁciency, mean midsleep time (a proxy for chronotype), and variability in midsleep time. Researchers gathered subjective data using the self-report Pittsburgh Sleep Quality Index and Insomnia Severity Index. Finally, fasting whole blood samples subjected to high-performance liquid chromatography were used to determine HbA1c as a measure of average blood glucose levels in the past 3 months.
Complete data were available for 172 patients. Higher levels of HbA1c were significantly associated with both short and long total sleep duration (U-shaped: β=-1.161 [P =.017]; β2=1.044 [P =.032]; R2, 4.3%). In addition, higher HbA1c was seen in individuals with lower sleep efficiency (β=-0.150 [P =.049]; R2, 2.3%), higher sleep variability (β=0.239 [P =.002]; R2, 4.9%), and worse subjective quality of sleep (β=0.191 [P =.012]; R2, 3.6%). Variability in sleep duration had the greatest standardized β coefficient of all sleep measures tested (0.222) and explained most of the variance in HbA1c (4.9%), followed by total sleep duration (4.3%), subjective sleep quality (3.6%), variability in midsleep time (3.4%), and sleep efficiency (2.3%). There were no associations found between HbA1c and insomnia symptoms or midsleep time.
The study sample consisted of individuals of primarily European descent who had a relatively short average sleep duration and high risk for sleep apnea, which may have had an impact on the ability to generalize results. In addition, investigators did not gather information on potential confounders such as timing of food intake, timing of exercise, treatment adherence, and self-care.
“In conclusion, sleep may be an important modiﬁable factor associated with HbA1c in patients with T2D who already receive regular care…[p]articularly variability in sleep duration, which may reﬂect partial sleep deprivation alternating with sleep compensation [and] be a promising therapeutic target,” the investigators concluded.
Brouwer A, van Raalte DH, Rutters F, et al. Sleep and HbA1c in patients with type 2 diabetes: which sleep characteristics matter most? [published online November 12, 2019]. Diabetes Care. doi:10.2337/dc19-0550