Sleep Apnea Increases Heart Disease Risk

Obstructive sleep apnea, or periodic interruptions in breathing throughout the night, thickens sufferers' blood vessels. Moreover, it increases the risk of several forms of heart and vascular disease. Emory researchers have identified the enzyme NADPH oxidase as important for the effects obstructive sleep apnea has on blood vessels in the lung.
The results are published in the May 1 issue of the American Journal of Respiratory Cell and Molecular Biology. C. Michael Hart, professor of medicine at Emory University School of Medicine and Atlanta Veterans Affairs Medical Center, is senior author.
Obstructive sleep apnea is thought to affect one in every 50 women and one in every 25 men in the United States. Standard treatment involves a mechanical application of air pressure. Anything that blunts sleep apnea’s effects on blood vessel physiology could reduce its impact on disease risk, Hart says.
Cyclically depriving mice of oxygen – researchers call this “chronic intermittent hypoxia” -- in a way that simulates obstructive sleep apnea gives them pulmonary hypertension. Pulmonary hypertension, which can be life threatening, is a condition in which the right side of the heart has trouble pumping blood because of resistance in the lung’s blood vessels.
Chronic intermittent hypoxia forces the blood vessels in the lung to make more NADPH oxidase, Hart and his colleagues found. Mice that lack NADPH oxidase are immune to hypoxia’s effects.
NADPH oxidase is a helpful enzyme because it is responsible for making superoxide, a reactive free radical that the immune system uses to kill bacteria. But superoxide also interferes with nitric oxide, a signal that allows blood vessels to relax.
Humans with mutations in genes for NADPH oxidase have recurrent bacterial infections because their ability to fight the bacteria is weakened. Thus Hart says inhibiting the NADPH oxidase enzyme in the entire body may be harmful, and he favors an indirect intervention.
"We think that strategies to lower NADPH oxidase expression induced by hypoxia may be useful in preventing hypoxia-induced pulmonary hypertension," says Hart.
The research was funded by the National Institutes of Health and the Veterans Affairs Research Service.

Sleep Apnea Patients Experience Higher Depression Levels

Patients who experience a range of ear, nose, and throat-related health problems exhibited a greater prevalence of depression than is observed in the general population, says new research presented at the 2008 American Academy of Otolaryngology – Head and Neck Surgery Foundation (AAO-HNSF) Annual Meeting %26amp; OTO EXPO in Chicago, IL.
In any given one-year period, approximately 9.5 percent of the population, or about 18.8 million American adults suffer from a depressive illness. The new study, which analyzed the health of 12,516 distinct otolaryngology patients, found that 30 percent of these patients either had been diagnosed with depressive illness or took antidepressants.
The study further broke down different otolaryngologic diagnoses to determine which conditions had the highest co-morbidity with depression.
Researchers found that patients diagnosed with sleep apnea had the highest levels of depression and use of antidepressant medications (21 percent and 46 percent).
Findings from this study could help clinicians diagnose and treat co-morbid depressive and otolaryngolic symptoms in patients.

Restless Leg Syndrome Interrupts Sleep for Fibromyalgia Patients

Researchers find that adults with fibromyalgia are 11 times more likely to suffer from restless leg syndrome (RLS) compared to individuals without the disease. The findings suggest treatment could help sleep and improve quality of life for adults diagnosed with the condition.
Dr. Nathaniel F. Watson, associate professor of neurology at the University of Washington in Seattle, Washington who contributed to the study says, "Sleep disruption is common in fibromyalgia, and often difficult to treat. It is apparent from our study that a substantial portion of sleep disruption in fibromyalgia is due to restless legs syndrome."

The study was led by Dr. Mari Viola-Saltzman of Loyola University Medical Center in Maywood, Ill. The team of scientists studied 172 people with fibromyalgia - 93 percent were female, with an average age of 50. They were compared to 63 healthy individuals with an average age of 41 years.

Sleep Problems more Severe with Fibromyalgia and RLS

Restless legs syndrome is characterized by the urge to move the legs, especially at night. The result is lack of sleep and worsening fatigue that already accompanies fibromyalgia.
The study looked at the prevalence of restless leg syndrome among in 172 people diagnosed with the disease. The researchers used the Pittsburgh Sleep Quality Index, Insomnia Severity Index and Epworth Sleepiness Scale to evaluate sleep disturbance among participants with RLS.
The authors note the study does not show fibromyalgia causes RLS, but the two diseases share similar sensory pathways that regulate the neurotransmitter dopamine. Exercise improves restless leg syndrome and also improves fibromyalgia. Another overlap could be the use of antidepressants prescribed for fibromyalgia treatment that can induce RLS.
The results show that sleep problems were more severe among fibromyalgia patients who also have Restless Leg Syndrome. The authors suggest clinicians routinely screen fibromyalgia patients for symptoms of Restless Leg Syndrome that is treatable and can "potentially improve sleep and quality of life..."