Researchers report that there is a statistically significant relationship between obstructive sleep apnea episodes occurring during rapid eye movement (REM) sleep and type 2 diabetes.
Obstructive sleep apnea is a sleep-related breathing disorder that involves a decrease or complete halt in airflow despite an ongoing effort to breathe. It occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway. This leads to partial reductions (hypopneas) and complete pauses (apneas) in breathing that can produce abrupt reductions in blood oxygen saturation. Brief arousals from sleep restore normal breathing but can cause a fragmented quality of sleep. Most people with obstructive sleep apnea snore loudly and frequently, and they often experience excessive daytime sleepiness.
Results of the research indicate that the adjusted odds ratio for type 2 diabetes was 2.0 times higher in patients with REM-related obstructive sleep apnea, defined as havng an REM apnea-hypopnea index (AHI) of 10 or more breathing pauses per hour of REM sleep. The prevalence of type 2 diabetes was 30.1 percent in participants with obstructive sleep apnea and 18.6 percent in those without obstructive sleep apnea; however, the overall association between obstructive sleep apnea and diabetes became non-significant after controlling for covariates such as body mass index (BMI), age, race and gender. Middle-aged participants with obstructive sleep apnea had an adjusted odds ratio for type 2 diabetes that was 2.8 times higher than younger or middle-aged people without obstructive sleep apnea. Hispanics and older patients referred for obstructive sleep apnea evaluation had a higher prevalence of type 2 diabetes; this relationship was not affected by obstructive sleep apnea.
According to principle investigator Kamran Mahmood, the researchers were surprised by the significant association of REM-related obstructive sleep apnea with type 2 diabetes.
“We believe that REM-related obstructive sleep apnea is a marker of early obstructive sleep apnea, especially in women and patients younger than 55 years,” said Mahmood. “Generally, obstructive sleep apnea is worse in REM sleep compared to non-REM sleep because of neurologically mediated impairment of skeletal muscles of upper airway and ventilation. This may be the reason for closer association of REM-related obstructive sleep apnea and type 2 diabetes.”
The study gathered data from 1,008 consecutive patients who were evaluated for obstructive sleep apnea by comprehensive polysomnography at the University of Illinois at Chicago; 66.9 percent were African American, 16.9 percent were Caucasian, 14.9 percent were Hispanic and 1.3 percent were Asian. obstructive sleep apnea was defined as an AHI of five or more breathing pauses per hour of sleep and was diagnosed in 745 individuals (74 percent); the 263 adults (26 percent) who did not have obstructive sleep apnea served as the control. Men comprised 52.8 percent of the obstructive sleep apnea group but only 28.5 percent of the control group.
According to the authors, the findings are consistent with several studies on the association of obstructive sleep apnea with glucose tolerance, insulin resistance and type 2 diabetes. REM-related obstructive sleep apnea is more common in mild-to-moderate cases of obstructive sleep apnea, especially in women and in patients younger than 55 years of age. Sleep fragmentation caused by obstructive sleep apnea may reduce REM sleep time, which could explain a high REM AHI.
Mahmood said that the results highlight the need to educate minority groups about obstructive sleep apnea and its complications. The authors encourage awareness campaigns and making obstructive sleep apnea screening part of all obesity management programs.
References:
1. Kamran Mahmood, et al. Prevalence of Type 2 Diabetes in Patients with Obstructive Sleep Apnea in a Multi-Ethnic Sample. The Journal of Clinical Sleep Medicine. Vol 5, 215-221.
