Sleep variability linked to blood sugar control in type 2 diabetes patients

The researchers showed a correlation between night-to-night sleep regularity (determined by actigraphy) and blood sugar control over a CGM period of 249 person-days. A one-hour increase in the standard deviation (SD) of nocturnal sleep duration over multiple nights was tied to about 1.1 mmol/L greater mean glucose value, 13% more TAR (time above range), and 12% less TIR (time in range) during the total CGM period.

Given the valuable role of sleep in blood sugar control, the investigation of the association between sleep and glycemic variability determined by CGM is worth doing in type 2 diabetes patients. Therefore, Yan Zhao and the research team from China aimed to examine whether sleep and circadian parameters and their night-to-night variations were linked with CGM-derived glycemic outcomes among T2D patients in real-life settings.

For this purpose, the researchers conducted CGM among 28 patients with type 2 diabetes aged 62.3±4.8 years, 57% women. Actigraphy was used to determine sleep characteristics within the CGM period. CGM-derived outcomes included blood sugar levels and percentages of TAR and TIR during the monitoring period. They also analyzed associations between intraindividual night-to-night variations of sleep characteristics and overall CGM results using linear regression. Linear mixed models were used to examine associations between sleep characteristics in each night and time-matched CGM outcomes.

The authors reported the following findings:

• A total of 249 person-days of CGM coupled with 221 nights of sleep characteristics were documented.
• A more significant standard deviation (SD) of objective sleep duration (minutes) between measurement nights was associated with higher glucose level (mmol/L, Coefficient 0.018), a smaller proportion of TIR (% in the observation period, -0.20), and a more significant proportion of TAR (0.22).
• Later sleep midpoint (minutes from 00:00) was associated with greater SD of glucose during the same sleep period (0.002), and longer nocturnal sleep duration was associated with a smaller coefficient of variance of glucose level in the upcoming day (%, -0.015).

"Minimizing night-to-night sleep and circadian variability, promoting an early chronotype, and securing sufficient sleep duration may be useful for optimizing blood sugar control among type 2 diabetes patients," the researchers wrote.

To conclude, objectively-determined sleep midpoint and duration and their daily variability are associated with CGM-derived blood sugar profiles in T2D patients.

Reference:

The study, "Objective sleep characteristics and continuous glucose monitoring profiles of type 2 diabetes patients in real-life settings," was published in Diabetes, Obesity and Metabolism.DOI: https://doi.org/10.1111/dom.14930