Sleep Disturbances Worsen Glucose Metabolism in Older Adults

THURSDAY , OCTOBER 8 2015

Sleep disturbances associated with insulin resistance and incidence of type 2 diabetes in older adults.

Sleep-disordered breathing (SDB), which includes loud snoring, stopping breathing for a while during sleep, and daytime sleepiness, and insomnia, has been linked to impaired glucose metabolism, insulin resistance, and an increase in incidence of type 2 diabetes (T2DM) in older adults. In this study, the authors consider the symptoms of both SDB and insomnia in their association with glucose metabolism in older populations.

A total of 5,888 participants over the age of 65 were recruited for this study. Participants were asked to report symptoms of SDB and insomnia. Symptoms of SDB were categorized as “observed apnea,” “bothersome snoring,” and “daytime sleepiness.” Insomnia symptoms include “sleep initiation problems,” sleep maintenance problems,” or “early morning awakenings.” In addition, an oral glucose tolerance test (OGTT) was performed to obtain fasting blood glucose and 2-h glucose value.

Results showed that there was a trend toward increased fasting glucose levels with an increasing number of SDB symptoms. Higher 2-h glucose values were observed in participants that experienced daytime sleepiness and in participants with an increasing number of SDB symptoms. The authors found that there was an inverse graded relationship between the number of SDB symptoms and insulin sensitivity.

In addition, they also found that participants who report SDB symptoms had increased risks of developing T2DM in a time-dependent manner. It is in a time-dependent manner because more recent exposure of observed apnea tended to be more strongly associated with subsequent risk of T2DM than with chronic exposure. The risk of developing T2DM was positively associated with observed apnea (HR 1.84 [95% CI 1.19-2.86]), snoring (HR 1.27 [95% CI 0.95-1.71]), and daytime sleepiness (HR 1.54 [95% CI 1.13-2.12]).

However, as opposed to previous studies, this study found no clear association between insomnia symptoms and insulin sensitivity or insulin secretion, except for an association of sleep maintenance problems with increased insulin secretion. They also did not find any association between insomnia and incidence of T2DM. Therefore, the authors suggest that more studies are needed to determine whether insomnia symptoms is associated with the incidence of T2DM in the elderly compared to younger adults.

Practice Pearls:

• Increasing number of SDB symptoms associated with higher 2-h glucose level and decreased insulin sensitivity.
• More recent exposure of sleep apnea is more strongly associated with subsequent risk of T2DM than with chronic exposure.
• No clear association between insomnia symptoms and insulin sensitivity or incident of T2DM.

Strand LB, Carnethon M, Biggs ML, et al. Sleep Disturbances and Glucose Metabolism in Older Adults: The Cardiovascular Health Study. Diabetes Care, 17 Sep 2015. Web. 20 Sep 2015.