May 4, 2020Public Health
According to an article published in the Journal of the American Heart Association (28 April 2020), African Americans with severe sleep apnea and other adverse sleep patterns are much more likely to have high blood glucose levels - a risk factor for diabetes - than those without these patterns. The findings suggest that better sleep patterns may lead to better blood glucose control and prove beneficial for type 2 diabetes prevention and diabetes management in African Americans, who are at higher risk for type 2 diabetes than other groups. They also point to the importance of screening for sleep apnea to help fight the potential for uncontrolled blood sugar in this high-risk group. Previous studies have linked disturbed sleep patterns, including sleep apnea, to increased blood glucose levels in white and Asian populations. But this new study is one of the few to use objective measurements to link these disturbed sleep patterns to increased blood glucose levels in black men and women.
For the study, the authors evaluated sleep patterns while concurrently measuring blood glucose markers among 789 black men and women who were enrolled in the Jackson Heart Study, the largest study of cardiovascular disease in African-Americans. Most of the participants - 74% - were women, 25% had type 2 diabetes, 20% were taking diabetes medication, and about 57% had a diagnosis of obstructive sleep apnea but were not receiving treatment for their condition. The mean age of study participants was 63 years.
Participants completed at-home sleep apnea tests, and each used a wrist actigraph watch, a tool that measures wakefulness and sleep, for seven days. The test calculated sleep duration (short vs long), sleep efficiency, night-to-night variability in sleep duration, and sleep fragmentation (multiple disruptions during sleep). The authors obtained several measures of glucose metabolism, including fasting blood glucose concentration, HbA1c levels, and insulin resistance. The study focused on four main groups: regular sleepers (no sleep apnea), those with mild sleep apnea, moderate sleep apnea, and severe sleep apnea. During the course of the study, it was found that those with the severe sleep apnea had 14% higher fasting blood glucose levels compared to those without sleep apnea. Severe sleep apnea was also associated with higher HbA1c levels.
In addition to evaluating sleep apnea, the study found that participants who experienced other types of disturbed sleep-including sleep fragmentation and sleep duration variability-were also more likely to have increased measures of blood glucose. The associations between disturbed sleep and high blood glucose levels were stronger in participants with diabetes compared to those without diabetes. In those without diabetes, disturbed sleep was also associated with increased insulin resistance. The study also found that associations of sleep apnea and high blood glucose levels were stronger among black men than black women. Black men with severe sleep apnea had 10% higher fasting blood glucose levels than black women with severe sleep apnea in the study.
The authors noted interventions that treat sleep apnea might help improve blood glucose management, including the use of continuous positive air pressure (CPAP) machines - devices that deliver air through a mask to keep the airway open when worn during sleep - and the encouragement of better sleep patterns in blacks, particularly in those with diabetes. But further studies will be needed to determine if such interventions will be effective.