Sleep Apnea Linked to High Blood Sugar in African-Americans

Andrey Popov@AdobeStock_233807292

According to a new study published in the Journal of the American Heart Association, African Americans with sleep disturbances are much more likely to experience changes in glucose metabolism which could predispose them to diabetes.

The study concurrently monitored the sleep quality and blood glucose metabolism of 789 black men and women who were enrolled in the Jackson Heart Study, the largest study of cardiovascular disease in African-Americans.

In order to characterize sleep quality, participants completed at-home sleep apnea tests using an actigraph wrist 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). Measures of glucose metabolism included fasting blood glucose concentration, HbA1c levels, and insulin resistance.

Results were grouped into four main categories: regular sleepers (no sleep apnea), those with mild sleep apnea, moderate sleep apnea, and severe sleep apnea. Those with severe sleep apnea were found to have 14% higher fasting blood glucose levels compared to those without sleep apnea. Severe sleep apnea was also associated with higher HbA1c levels.

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; however, in those without diabetes, disturbed sleep was associated with increased insulin resistance.

Researchers also observed gender-based differences in the data.  Black men with severe sleep apnea had 10% higher fasting blood glucose levels than black women with severe sleep apnea in the study.

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. Their mean age was 63 years.

Disturbed sleep patterns, including sleep apnea, have previously been linked to increased blood glucose levels in white and Asian populations. But this study is one of the few to use objective measurements to connect sleep patterns to increased blood glucose levels in black men and women, the researchers said.

Researchers say the findings suggest that better sleep habits may 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.

"The study underscores the importance of developing interventions to promote regular sleep schedules, particularly in those with diabetes," said Yuichiro Yano, M.D., Ph.D., the lead study author and a researcher in the Department of Family Medicine and Community Health at Duke University. "It also reaffirms the need to improve the screening and diagnosis of sleep apnea, both in African Americans and other groups."

Yano Y, Gao Y, Johnson DA, et al. Sleep Characteristics and Measures of Glucose Metabolism in Blacks: The Jackson Heart Study [published online ahead of print, 2020 Apr 28]. J Am Heart Assoc. 2020;e013209. doi:10.1161/JAHA.119.013209