Sleep Experts Seek Sleep Apnea, Diabetes Link
Researchers are seeking clues to determine if maligned fat cells in certain patients are actually secreting substances which may have protective and preventive effects for certain conditions.
Sleep medicine experts at The Ohio State University Medical Center are investigating blood glucose levels and the role of fat cells in patients with obstructive sleep apnea (OSA), a common sleep disorder in which breathing is interrupted for brief periods during sleep when the airway becomes occluded.
"Obstructive sleep apnea is strongly associated with the risk of having diabetes, and this association appears to be independent of obesity, which is a common factor for both conditions," says Dr. Ulysses Magalang, medical director of Ohio State's Sleep Disorders Center.
"We do not know whether obstructive sleep apnea causes diabetes. What we do know is that patients with sleep apnea have an increased insulin resistance, a hallmark of patients with diabetes and also a known risk factor for heart disease," adds Magalang, who has been conducting a study involving obstructive sleep apnea patients using continuous positive airway pressure treatment and its effects on the blood levels of substances secreted by fat cells.
"In the past, fat cells were thought of as simply inactive sites for storage of energy, but we now know that they actually secrete a variety of substances with significant effects on the body's metabolism," says Magalang, also a pulmonologist and critical care specialist at the Medical Center. "While most of these substances have undesirable effects, others may have the opposite reactions and improve insulin resistance and even prevent atherosclerosis.
"It is of great interest to us that the levels of some of these substances secreted by fat cells with desirable effects go down with increasing obesity and also in our patients with obstructive sleep apnea," adds Magalang.
Repetitive dipping of blood oxygen levels and the associated brain arousals result in common symptoms, such as lack of concentration, sleepiness and fatigue. OSA has been implicated as a risk factor for a variety of other conditions including heart disease, stroke and diabetes.
Continuous positive airway pressure treatment has been proven effective, but only roughly 60 percent of patients with obstructive sleep apnea will be compliant long-term, according to Magalang.
Continuous positive airway pressure forces air into the nasal passages, via a pump, at a pressure high enough to withstand obstructions in the airway. The airway pressure stimulates normal breathing, during both inspiration and expiration.
In addition to using the breathing masks at night, some patients resort to wearing dental devices or undergo surgery to prevent airway blockage.
"Understanding the basic mechanics of why insulin resistance develops in patients with OSA is important because it will help develop new treatment strategies for improving blood glucose control and, perhaps, prevent cardiovascular disease in these patients," Magalang says.