Category: Obstructive Sleep Apnea

A study in the Feb. 1 issue of the journal Sleep found gray matter concentration deficits in multiple brain areas of people with severe obstructive sleep apnea (OSA). The study suggests that the memory impairment, cardiovascular disturbances, executive dysfunctions, and dysregulation of autonomic and respiratory control frequently observed in OSA patients may be related to morphological changes in brain structure.

Results indicate that in newly diagnosed men with severe OSA, gray matter concentrations were significantly decreased in multiple brain areas, including limbic structures, prefrontal cortices and the cerebellum. Optimized voxel-based morphometry, an automated processing technique for magnetic resonance imaging (MRI), was used to characterize structural differences in gray matter by examining the entire brain, rather than a particular region.

"Gray matter" refers to the cerebral cortex, where most information processing in the brain takes place. It is a layer of tissue that coats the surface of the cerebrum and the cerebellum and is gray in appearance, lacking the myelin insulation that makes most other parts of the brain appear to be white.

Principal investigator Seung Bong Hong, MD, PhD, professor of neurology at the Samsung Medical Center in Sungkyunkwan University School of Medicine in Seoul, South Korea, said the study emphasizes the importance of diagnosing and effectively treating severe OSA.

"Poor sleep quality and progressive brain damage induced by OSA could be responsible for poor memory, emotional problems, decreased cognitive functioning and increased cardiovascular disturbances," said Hong. "The use of continuous positive airway pressure — CPAP — therapy could stop further progression of brain damage in patients with severe OSA."

The study involved 36 male OSA patients with an average age of 44.7 years and 31 healthy, male, age-matched controls. Sleep was evaluated by overnight polysomnography. The OSA patients had a mean apnea-hypopnea index (AHI) of 52.5 partial and complete breathing pauses per hour of sleep; an AHI of more than 30 is considered severe OSA. Patients with OSA also had more awakenings from sleep and a more fragmented sleep structure than controls.

Surprisingly, gray matter concentration was decreased in OSA patients without significant changes in gray matter volume. According to the authors, frequent episodes of nocturnal hypoxemia and hypercarbia induce vasodilation and disturbances in the autoregulation of the brains of OSA patients. Therefore, changes in the brain volume of OSA patients may be obscured by increased cerebral blood volume or whole brain water content from OSA-induced changes in autoregulation.

According to the American Academy of Sleep Medicine, OSA 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. Most people with OSA snore loudly and frequently, and they often experience excessive daytime sleepiness. The treatment of choice for OSA is CPAP therapy, which provides a steady stream of air through a mask that is worn during sleep. This airflow keeps the airway open to prevent pauses in breathing and restore normal oxygen levels.

The authors noted that more research is needed to determine if gray matter concentration loss occurs as a consequence of sleep apnea, or if preexisting abnormalities may contribute to the development of the disorder.

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Journal Reference:

1. Eun Yeon Joo et al. Reduced Brain Gray Matter Concentration in Patients With Obstructive Sleep Apnea Syndrome. Sleep, 2010;33(2):235-241 [link]

There is a high prevalence of nocturnal teeth grinding, or bruxism, in patients with obstructive sleep apnea (OSA), particularly in Caucasians.

New research presented at CHEST 2009, the 75th annual international scientific assembly of the American College of Chest Physicians (ACCP), found that nearly 1 in 4 patients with OSA suffers from nighttime teeth grinding; this seems to be especially more prevalent in men and in Caucasians compared with other ethnic groups.

It is estimated that 8 percent of the general US population suffers from bruxism, a condition frequently associated with a preexisting dental or jaw disorders, as well as stress.

"The relationship between obstructive sleep apnea and sleep bruxism is usually related to an arousal response. The ending of an apneic event may be accompanied by a number of mouth phenomena, such as snoring, gasps, mumbles, and teeth grinding," said Shyam Subramanian, MD, FCCP, Baylor College of Medicine, Houston, TX. "Men typically have more severe sleep apnea, and perhaps may have more arousal responses, which may explain the higher prevalence of teeth grinding in men. Besides, men characteristically tend to report more symptoms of sleep apnea than women, such as snoring, loud grunting, and witnessed apneas."

Other factors that might help explain the relationship between sleep apnea and teeth grinding include anxiety and caffeine use.

"High levels of anxiety can lead to bruxism, and untreated sleep apnea is known to cause mood disturbances including depression and anxiety," said Dr. Subramanian. "Daytime sleepiness from sleep apnea may cause a person to ingest caffeine, and this has also been associated with a high risk of bruxism."

Through a retrospective chart review, Dr. Subramanian and his colleagues, from the Baylor College of Medicine, Houston, TX, assessed the prevalence of bruxism and gastroesophageal reflux (GERD) in 150 men and 150 women with OSA. Each group consisted of 50 Caucasians, 50 African-Americans, and 50 Hispanics. Results showed that 25.6 percent of patients suffered from teeth grinding, while 35 percent of all patients with OSA complained of nocturnal heartburn and GERD symptoms.

The researchers also examined the influence of gender and ethnicity on OSA, GERD, and bruxism. They found that bruxism was higher in men than in women — 43 percent vs. 31 percent. Caucasians had the highest rate of bruxism compared to other ethnic groups — 35 percent vs. 19 percent in Hispanics. African-Americans have the highest prevalence of GERD — 40 percent vs. 31 percent in the Hispanic population and 34 percent in Caucasians. Overall, no correlation was observed between the presence of self-reported GERD and bruxism.

Untreated bruxism can lead to excessive tooth wear and decay, periodontal tissue damage, jaw pain, and temporomandibular joint or TMJ pain, headaches, and sleep disturbances for patients and their bed partners.

"Bruxism can be both a daytime syndrome as well as a nighttime syndrome, but it is bruxism during sleep, including short naps, that causes the majority of health issues," said Dr. Subramanian. "Studies do suggest that when sleep bruxism is related to OSA, certain therapies, including continuous positive airway pressure, may eliminate bruxism during sleep."

"Sleep disorders such as sleep apnea can lead to many secondary health conditions," said Kalpalatha Guntupalli, MD, FCCP, President of the American College of Chest Physicians. "When treating sleep apnea, clinicians must also recognize and address secondary health conditions, such as bruxism, in order to fully manage a patient's sleep disorder."

Golfers who undergo treatment for sleep apnea may improve their golf game as well as their overall health, shows new research.

A new study presented at CHEST 2009, the 75th annual international scientific assembly of the American College of Chest Physicians (ACCP), found that golfers with obstructive sleep apnea (OSA) who received nasal positive airway pressure (NPAP) for their disorder improved their daytime sleepiness scores and lowered their golf handicap by as much as three strokes. Researchers suggest that the possibility of improving your golf game may be a significant motivator to improve NPAP compliance rates among golfers.

"More so than many sports, golf has a strong intellectual component, with on-course strategizing, focus, and endurance being integral components to achieving good play," said Marc L. Benton, MD, FCCP, Atlantic Sleep and Pulmonary Associates, Madison, NJ. "OSAS can lead to daytime sleepiness, fatigue, and cognitive impairment, all side effects which can negatively impact a person's ability to golf to the best of one's ability."

Dr. Benton and colleague Neil S. Friedman, RN, RPSGT, from Morristown Memorial Hospital, Madison, NJ, evaluated the impact of NPAP on the golf handicap index (HI) of 12 golfers with diagnosed moderate to severe OSA. HI was recorded upon study entry, as was the Epworth sleepiness scale (ESS), a validated questionnaire used to assess daytime sleepiness, and a sleep questionnaire (SQ) developed by the authors. After 20 rounds of golf while receiving NPAP treatment (approximately 3 to 5 months), the treatment group demonstrated a significant drop in average HI, 12.4 (+/- 3.5) to 11.0 (+/- 4.7). Patients in the study group also improved their ESS score, 11.8 (+/- 6.6) to 5.5 (+/- 3.6), and the SQ score, 14.3 (+/- 7.5), to 3.1 (+/- 3.1). A control group of 12 subjects demonstrated no change in HI, ESS score, or SQ score during this study.

"As any golfer knows, when your ability to think clearly or make good decisions is compromised, the likelihood of playing your best is greatly diminished," said Dr. Benton. "Through treatment with NPAP, we can improve many cognitive metrics, such as attention span, memory, decision-making abilities, and frustration management, which may, in turn, positively affect a person's golf game."

Results of the study also showed that the best golfers, defined as HI <12, had the biggest improvements in their game. Within this group, the average HI dropped from 9.2 (+/- 2.9) to 6.3 (+/- 3.0); the SQ score from 10.8 (+/- 1.9), to 2.8 (+/- 2.6).

"The biggest handicap improvements occurred in the lower handicap, often older golfers. This group typically would be expected to trend in the opposite direction due to age-related deterioration in strength and endurance," said Mr. Friedman. "The drop in handicap among the better golfers probably reflected that the major limiting factor was not golf skill but cognitive compromise that improved when the sleep apnea was treated."

Dr. Benton estimates that there are 1 to 3 million regular golfers (regular defined as 10 or more rounds per year) who have OSA, and most are undiagnosed or untreated. However, even when proper treatment is offered, it is only effective if it is used regularly. In men, studies have reported compliance rates as low as 40 percent. Patients cite many reasons for noncompliance with NPAP, including discomfort, inconvenience, cost, noise, or embarrassment. In the current study, nearly all patients in the treatment group had a compliance rate of above 90 percent.

"Providers typically attempt to maximize compliance with NPAP by promoting its medical benefits or warning patients of the risks involved in not being treated, but this approach does not always work," said Dr. Benton. "In the case of this study, the possibility of improving one's ability to play golf appears to have been a significant motivation to improve treatment compliance."

"Compliance with CPAP therapy is an ongoing issue in the treatment of patients with sleep apnea," said Kalpalatha Guntupalli, MD, FCCP, President of the American College of Chest Physicians. "Finding new and more effective ways to increase CPAP compliance based on individual motivations is definitely encouraged."

According to research recently published by an Oregon Health & Science University scientist, a form of surgery called uvopalatopharyngoplasty is effective for treating certain patients who suffer from sleep apnea, one of the most common sleep disorders. The research, conducted in collaboration with scientists at the Mayo Clinic, is published in the September issue of the Mayo Clinic Proceedings.

Sleep apnea is a common disorder in which the tissues at the back of the throat temporarily collapse during sleep. This causes breathing to repeatedly stop and start during the night and often leads to poor-quality sleep and daytime drowsiness. It is estimated that approximately 4 percent of men and 2 percent of women suffer from sleep apnea. In many cases, sleep apnea patients are prescribed a continuous positive airway pressure machine, or CPAP. The machine counters the effects of sleep apnea by forcing the airway to remain open by blowing air through the throat tissues via a facemask.

"The CPAP device can be an effective form of treatment," explained Akram Khan, M.D., an assistant professor of pulmonary and critical care medicine in the OHSU School of Medicine. "However, many patients report they have trouble falling asleep while wearing the facemask or they take the device off after only a few hours of sleep. This latest research helps us identify the patients who are the best candidates for surgery as an alternative to a CPAP. Specifically, we were able to identify patients whose sleep apnea would likely be greatly diminished or resolved by receiving uvopalatopharyngoplasty surgery."

The procedure involves a tonsillectomy along with additional surgery to the palate and uvula. This is done to diminish the constriction of the throat tissues during sleep.

By observing the results of sleep studies for 63 patients several weeks pre and post surgery at the Mayo Clinic, Khan and his colleagues found there are certain patient characteristics that can increase the likelihood of a successful surgical outcome. For instance, patients who are young and have a body mass index (BMI) in the normal to mildly obese range are more likely to have a successful outcome.

The research also suggests that surgical candidates with the greatest likelihood of success would have a moderate level of breathing stoppages per hour – referred to as the apnea-hypopnea (AHI) index. They suggest that a patient with an AHI range of 30 to 35 episodes per hour would be the best candidates for surgery.

"We believe that for a certain segment of sleep apnea patients, this research demonstrates that surgery is a viable alternative to CPAP," added Khan. This is important information for physicians as they discuss possible sleep apnea therapies with their patients."

 Ordinary, loud snoring doesn’t seem to be harmful, according to the September issue of Mayo Clinic Health Letter. But snorers still may want to seek treatment to stop snoring, reduce embarrassment and improve sleep for themselves and their bed partner.

Snoring is caused by relaxed and sagging tissues. As sleep deepens, the tongue relaxes, as do the soft tissues of the throat and the roof of the mouth (soft palate). The tissues can sag into the airway, causing it to narrow. As air is inhaled or exhaled through the narrowed opening, the relaxed tissues of the soft palate vibrate. The result is snoring. Though most snoring is harmless, snorers should consult a doctor to rule out sleep apnea, a serious health concern where breathing stops during sleep.

For ordinary snoring, a doctor will likely discuss conservative treatment options first. Assistive devices or, as a last resort, surgery, can help reduce snoring. Mayo Clinic Health Letter covers these treatment approaches:

Lose weight: Extra bulk narrows airways, contributing to snoring.

Avoid alcohol: Alcohol consumption can cause excessive muscle relaxation. Avoiding alcohol for at least four hours before bedtime may help.

Relieve nasal obstruction: Adhesive nasal strips (Breathe Right, others) or corticosteroid nasal sprays can help reduce nasal obstruction that can contribute to snoring.

Change sleep positions: In back sleepers, the tongue can sag and narrow the airway during sleep. A doctor can suggest techniques to learn to sleep comfortably in other positions.

Stop smoking: Smoking is associated with an increased risk of snoring. People who stop have a lower rate of snoring.

Try assistive devices: The most effective treatment for snoring is a continuous positive airway pressure (CPAP) machine. It delivers pressurized air through a mask, keeping the upper airway open during sleep. Some people have difficulty wearing a mask at night. An oral appliance from a specially trained dentist or orthodontist can help keep the throat open, too, and may be less obtrusive than a CPAP machine.

Consider surgery: Several surgical procedures can help reduce snoring, either by cutting away excess mouth and throat tissue or by stiffening tissues of the soft palate to prevent vibration and sagging. Surgery is considered a last resort because it can cause side effects and complications. Typically, there’s only a 50 percent chance that snoring will improve over the long term.

A study in the Aug. 15 issue of the Journal of Clinical Sleep Medicine shows that adults with Down syndrome also frequently suffer from obstructive sleep apnea (OSA). However, complications of untreated OSA such as cardiovascular disease, daytime sleepiness and impaired cognitive functioning overlap with the manifestations of Down syndrome; therefore, OSA may not be detected.

Results indicate that 94 percent of subjects with Down syndrome had OSA; 88 percent had at least moderate OSA with an apnea-hypopnea index (AHI) of more than 15 breathing pauses per hour of sleep; and 69 percent had severe OSA with an AHI of more than 30. Twelve of the 16 subjects with Down syndrome were obese, and there was a significant correlation between body mass index (BMI) and AHI. Total sleep time in subjects with Down syndrome (307 minutes) was more than an hour less than in controls (380 minutes). Despite the severity of OSA in the study group, medical evaluation had been sought in only one case.

According to senior author Carole Marcus, M.B.B.Ch., professor of pediatrics at the University of Pennsylvania and director of the Children's Hospital of Philadelphia Sleep Center, it is well known that children with Down syndrome are at risk for OSA, with a prevalence of 30 to 55 percent, and adults with Down syndrome have even more predisposing factors for OSA than children, as they still have the craniofacial anomalies and are more likely to be obese or hypothyroid.

"Patients with Down syndrome have a great deal of risk factors for OSA (based on their narrow midface, large tongue, floppy muscle tone, tendency towards being overweight, and thyroid disease)," said Marcus. "However, the fact that almost all of the subjects studied had OSA was a much higher prevalence than we expected. It was surprising how severe the illness was, and how the OSA was unsuspected by their caregivers."

The cohort study included information from 16 adults with DS who underwent evaluation for sleep disordered breathing. Subjects were recruited from the local association of Retarded Citizens (ARC), parents of Down Syndrome (PODS) group meetings and the Kennedy Krieger Down Syndrome Clinic. Eight subjects were recruited from the clinic while the other eight responded to fliers and letters. Participants ranged between 19 and 56 years of age with a median age of 33. Half of the subjects were female (four of whom were postmenopausal); 15 were Caucasian, and one was Asian.

Polysomnographic results were matched and compared to a retrospective control sample of 48 adult patients who underwent standard diagnostic nocturnal polysomnography at the John Hopkins University adult Sleep Center for evaluation of suspected OSA. Controls had less severe sleep apnea with a median AHI of 16; 54 percent had an AHI of more than15; 38 percent had an AHI of more than 30.

The authors suggest that obesity, a common and potentially treatable problem in Down syndrome, appears to play an important role in the pathophysiology of OSA in this population.

According to the American Academy of Sleep Medicine, OSA 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. Most people with OSA snore loudly and frequently, and they often experience excessive daytime sleepiness.

A study in the journal Sleep has identified a distinct ECG-derived spectrographic phenotype, designated as narrow-band elevated low frequency coupling (e-LFCNB), that is associated with prevalent hypertension, stroke, greater severity of sleep disordered breathing and sleep fragmentation in patients suffering from obstructive sleep apnea (OSA).

Results indicate that the odds ratio for prevalent stroke was 1.65 in those with versus without the presence of e-LFCNB. The biomarker was detected in 1,233 participants (23.5 percent), with statistically significant differences between those with and without it. Patients with the biomarker tended to be older (average 64.7 years versus 61.4 years), male (63.3 percent versus 45.1 percent), slightly heavier (average body mass index 29.3 versus 28.6) and sleepier (according to the Epworth Sleepiness Score test results). Sleep apnea severity and use of diuretics, calcium blockers, and B-blockers were associated with increased e-LFCNB. After adjustment for age, sex, body mass index, hypertension, and diabetes, only prevalent stroke remained associated with both categorical and continuous measures of e-LFCNB, while treated and total hypertension were associated only with the ECG biomarker as continuous measure.

According to lead author Robert J. Thomas, MD, assistant professor of medicine at the Beth Israel Deaconess Medical Center & Harvard Medical School in Boston, Mass., the electrocardiogram (ECG)-based technique allows the tracking of interactions ("coupling") of breathing amplitude and heart-beat rate changes, which are both influenced by sleep, thus providing a 'map' of sleep behaviors. Use of this technique allows physicians to assign patients with sleep apnea into groups who have or do not have breathing control abnormalities.

"Central sleep apnea is precisely timed, meaning that breathing stops and starts with near identical timing from event-to-event," said Thomas. This type of timing abnormality results in the narrow-band pattern, even if by usual scoring methods the respiratory abnormality looks obstructive." We found that having the pattern suggesting a central or breathing control abnormality was associated with worse sleep, more severe sleep apnea, high blood pressure and an increased risk of prevalent strokes. Therefore, OSA patients who are at increased risk for high blood pressure may be at even greater risk if they also have a control abnormality."

The cross-sectional retrospective study obtained polysomnographic and clinical data from 5,247 patients (of the original 6,441) who were included in the baseline examination of the Sleep Heart Health Study (SHHS), a multi-center longitudinal study of participants over the age of 40, designed to determine the cardiovascular consequences of sleep apnea at a population level. Associations were estimated with use of various drugs and pathologies including prevalent hypertension and cardiovascular and cerebrovascular disease.

According to the study, the ECG-derived spectrogram's detection of periodic breathing-type respiratory oscillations exceeds that identified by visual detection of periodic breathing. Conventional scoring may be biased toward the scoring of obstructive hypopneas during periods of periodic breathing, and measurement of the biomarker could bring attention to parts of the polysomnogram where the probability of periodic breathing or central apneas is high. The spectrogram is automated, objective, and capable of mapping the spectral dispersion of low-frequency, coupled cardiopulmonary oscillations; therefore, it could be a more accurate marker of periodic breathing and could provide insights into sleep physiology and pathology.

The authors claim that there is an increased prevalence of periodic breathing following ischemic cerebrovascular disease, which is one way by which strokes may cause an increase in the biomarker. Hypertension may be the cause of undiagnosed cardiac dysfunction, which may also lead to an increase in the presence of e-LFCNB.

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Journal Reference:

1. . Prevalent Hypertension and Stroke in the Sleep Heart Health Study: Association with an ECG-derived Spectrographic Marker of Cardiopulmonary Coupling. Sleep, July 1, 2009

Stroke patients with obstructive sleep apnea (OSA) who undergo treatment with continuous positive airway pressure (CPAP) following their stroke may substantially reduce their risk of death, according to Spanish research to be published in the July 1 issue of the American Journal of Respiratory and Critical Care Medicine.

"Our results suggest that patients with ischemic stroke and moderate to severe OSA showed an increased mortality risk," wrote lead author, Miguel Angel Martínez-García, M.D., of Requena General Hospital in Valencia, Spain. "CPAP treatment, although tolerated by only a small percentage of patients, is associated with a reduction in this excess risk and achieves a mortality [rate] similar to patients without OSA or with mild disease."

The study identified and recruited 166 consecutive patients from Requena General Hospital who had had an ischemic stroke and subsequently were diagnosed with sleep apnea in sleep study tests. The mean age was 73.3. CPAP treatment was offered to the 96 patients who scored above 20 on the apnea-hypopnea index, indicating moderate-to-severe OSA. Each patient was followed for five years, reporting to the outpatient clinic and one, three and six months, then at six month intervals until the conclusion of the study. They were evaluated for general status, new cardiovascular events, CPAP adherence and death.

At the conclusion of the five year follow-up period, nearly half (48.8 percent) the original study group had died and only 28 of the original 96 were considered to be fully compliant with CPAP treatment. After adjusting for 13 potentially confounding variables, including age, gender, co-morbidities and current smoking, the researchers found that those with moderate to severe OSA who had not complied with CPAP treatment had nearly 1.6 times the risk of death compared to patients who tolerated CPAP, whereas those with moderate-to-severe disease who had tolerated CPAP had similar risk of death than patients without sleep apnea or mild disease.

"Our results suggest that moderate to severe OSA in patients with stroke has an unfavorable effect on long-term mortality. CPAP treatment is associated with a reduction in this excess risk," concluded Dr. Martínez-García in the article.

However, while the researchers controlled for the measurable variables they anticipated as potentially contributing to the link between CPAP compliance and risk of death following stroke, they acknowledge that certain variables were impossible to adequately anticipate or measure. "Patients who did not tolerate CPAP might have a special profile; [they] may have poor adherence to other types of treatment, including treatment of cardiovascular prevention, which would carry with it a higher risk of stroke," said Dr. Martínez-García. "However, the variables that measure the adherence of all the treatments in these patients are very difficult to analyze because patients often take many medications. This is a limitation of our study."

Further research in the form of a long-term, multi-center study with enough statistical power to verify the effect of CPAP on mortality in these patients is necessary before drawing any direct causal link between CPAP treatment and risk of death after stroke, said Dr. Martínez-García.

Other important goals should be immediately improving CPAP compliance within the elderly stroke population, he suggested. "One of the most important objectives is to increase CPAP adherence to treatment in stroke patients. This is a very difficult objective because of the special characteristics of stroke patients, who tend to be elderly, may have neurological damages, and whose symptoms related to sleep apnea are less likely to rapidly improve with CPAP," said Dr. Martínez-García. "Spending time to explain the benefits of treatment in terms of cardiovascular prognosis, being in direct contact with them, educational programs, offering them the possibility of sleep lab assessments if they have problems with CPAP treatment and improvements in the comfort of the devices would be the activities could do to improve the adherence to CPAP treatment."

A multi-ethnic study in the June 15 issue of the Journal of Clinical Sleep Medicine reports that there is a statistically significant relationship between obstructive sleep apnea (OSA) episodes occurring during rapid eye movement (REM) sleep and type 2 diabetes.

Results indicate that the adjusted odds ratio for type 2 diabetes was 2.0 times higher in patients with REM-related OSA, 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 OSA and 18.6 percent in those without OSA; however, the overall association between OSA and diabetes became non-significant after controlling for covariates such as body mass index (BMI), age, race and gender. Middle-aged participants with OSA had an adjusted odds ratio for type 2 diabetes that was 2.8 times higher than younger or middle-aged people without OSA. Hispanics and older patients referred for OSA evaluation had a higher prevalence of type 2 diabetes; this relationship was not affected by OSA.

According to principle investigator Kamran Mahmood, MD, MPH, of the University of Illinois at Chicago, the researchers were surprised by the significant association of REM-related OSA with type 2 diabetes.

"We believe that REM-related OSA is a marker of early OSA, especially in women and patients younger than 55 years," said Mahmood. "Generally, OSA 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 OSA and type 2 diabetes."

The study gathered data from 1,008 consecutive patients who were evaluated for OSA 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. OSA 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 OSA served as the control. Men comprised 52.8 percent of the OSA 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 OSA with glucose tolerance, insulin resistance and type 2 diabetes. REM-related OSA is more common in mild-to-moderate cases of OSA, especially in women and in patients younger than 55 years of age. Sleep fragmentation caused by OSA 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 OSA and its complications. The authors encourage awareness campaigns and making OSA screening part of all obesity management programs.

According to the American Academy of Sleep Medicine, OSA 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 OSA snore loudly and frequently, and they often experience excessive daytime sleepiness.

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Journal Reference:

1. . Prevalence of Type 2 Diabetes in Patients with Obstructive Sleep Apnea in a Multi-Ethnic Sample. Journal of Clinical Sleep Medicine, June 15, 2009

A study in the June 15 issue of the Journal of Clinical Sleep Medicine shows that the complaints of fatigue and tiredness in patients with obstructive sleep apnea (OSA) improved significantly with good adherence to continuous positive airway pressure (CPAP) therapy, suggesting that – like the symptom of excessive daytime sleepiness – these complaints are important symptoms of OSA.

Results indicate that good adherence to CPAP therapy for an average of five or more hours per night resolved baseline complaints of fatigue in 45 of 80 participants (56 percent), tiredness in 56 of 96 participants (58 percent) and sleepiness in 48 of 72 participants (67 percent); improvement of each symptom was significantly better among CPAP-adherent participants than among inadequately treated subjects. A baseline complaint of lack of energy also was resolved in 47 of 100 participants with good CPAP adherence, but this improvement failed to reach statistical significance when compared with inadequately treated participants.

According to senior investigator Ronald D. Chervin, M.D., M.S., of the Michael S. Aldrich Sleep Disorders Laboratory in Ann Arbor, Mich., physicians should consider the possibility of OSA as a treatable underlying cause not just for the complaint of sleepiness, but also for the chief complaints of fatigue, tiredness and lack of energy.

"We found that sleep apnea patients who used their CPAP regularly, in comparison to those who did not, had much greater success in reducing their fatigue, tiredness and sleepiness," he said. "This suggests that sleep apnea may be the cause of these symptoms, as it is a cause of sleepiness."

The study involved 313 OSA patients with an average age of 54.7 years; 178 (56.9 percent) were men. It compared 183 participants who reported using CPAP for an average of five or more hours per night with 96 subjects who either had no active treatment (55 subjects) or reported using CPAP for an average of less than five hours per night (41 subjects); 34 participants were excluded from the analysis because they received a treatment other than CPAP.

Compared with inadequately treated patients, participants who had good adherence to CPAP had a higher severity of OSA at baseline and lower self-reported sleepiness at follow-up. Both before and after treatment, women reported a complaint of lack of energy statistically more often than men.

According to the American Academy of Sleep Medicine, OSA 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. Most people with OSA snore loudly and frequently, and they often experience excessive daytime sleepiness.

The authors suggest that their findings are in agreement with previous research demonstrating that CPAP adherence is associated with improvements in OSA symptoms, daytime sleepiness, cognitive impairments, blood pressure and quality of life.

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Journal Reference:

1. . Fatigue, Tiredness and Lack of Energy Improve with Treatment for OSA. Journal of Clinical Sleep Medicine, June 15, 2009