Obstructive sleep apnea may directly cause early cognitive decline

by Frontiers

Credit: Unsplash/CC0 Public Domain

Obstructive sleep apnea (OSA) is a potentially dangerous condition. During sleep, the throat muscles of people with OSA relax and block the airflow into the lungs, so that they repeatedly stop breathing. Common symptoms of OSA include restless sleep, loud snoring, daytime sleepiness, and prolonged headaches in the morning—highly debilitating for patients and their partners.

09 april 2023--OSA is currently underdiagnosed: it may occur in as much as 15 to 30% of men and 10 to 15% of women, or approximately 1 billion adults worldwide, of whom an estimated 80% don't know they have it. Major risk factors for OSA include middle or old age, being obese, smoking, chronic nasal blockage, high blood pressure, and being male.

Now, researchers from the UK, Germany, and Australia have shown for the first time that in middle-aged men, OSA can also cause early cognitive decline, even in patients who are otherwise healthy and not obese. The results are published in Frontiers in Sleep.

"We show poorer executive functioning and visuospatial memory and deficits in vigilance, sustained attention, and psychomotor and impulse control in men with OSA. Most of these deficits had previously been ascribed to co-morbidities," said Dr. Ivana Rosenzweig, a neuropsychiatrist who heads the Sleep and Brain Plasticity Centre at King's College London, and the lead author of the study.

"We also demonstrated for the first time that OSA can cause significant deficits in social cognition."

Rare cohort without co-morbidities

Rosenzweig and colleagues studied a group of 27 men between the ages of 35 and 70 with a new diagnosis of mild to severe OSA but without any co-morbidities. Such patients are relatively rare, because most men and women with OSA have co-morbidities such as cardiovascular and metabolic disease, stroke, diabetes, chronic systemic inflammation, or depression.

The men were not currently smokers or alcohol abusers, and were not obese (i.e., with a body mass index (BMI) below 30). As a control, the researchers studied a group of seven age-, BMI-, and education-matched men without OSA. The OSA diagnosis was confirmed by a so-called WatchPAT test of their respiratory function during sleep at home, and also by video-polysomnography at King's College sleep center.

With the latter method, the brain waves of sleeping subjects were measured by electroencephalography (EEG), while their blood oxygen levels, heart rate, breathing, and eye and leg movements were tracked.

The scientists also tested the subjects' cognitive function with the CANTAB or 'Cambridge Neuropsychological Test Automated Battery' of tests.

Premature cognitive decline

The results showed that patients with severe OSA had poorer vigilance, executive functioning, short-term visual recognition memory, and social and emotion recognition than the matched controls. Patients with mild OSA performed better in these domains than patients with severe OSA, but worse than the controls.

"The most significant deficits…were demonstrated in the tests that assess both simultaneous visual matching ability and short-term visual recognition memory for non-verbalizable patterns, tests of executive functioning and cued attentional set shifting, in vigilance and psychomotor functioning, and lastly, in social cognition and emotion recognition," wrote the authors.

The authors conclude that OSA is sufficient to cause these cognitive deficits, which previous studies had attributed to the most common co-morbidities of OSA such as systemic hypertension, cardiovascular and metabolic diseases, and type 2 diabetes.

Unclear mechanism

But what is the mechanism by which OSA causes premature cognitive decline? The authors speculated that the cognitive deficits are due to intermittent low oxygen and high carbon dioxide in the blood, changes in blood flow to the brain, sleep fragmentation, and neuroinflammation in OSA patients.

"This complex interplay is still poorly understood, but it's likely that these lead to widespread neuroanatomical and structural changes in the brain and associated functional cognitive and emotional deficits," said Rosenzweig.

Whether co-morbidities have similar negative effects on cognition above and beyond those caused directly by OSA is not yet clear.

"Our study is a proof of concept. However, our findings suggest that co-morbidities likely worsen and perpetuate any cognitive deficits caused directly by OSA itself," said Rosenzweig.

"What remains to be clarified in future studies is whether co-morbidities have an additive or synergistic effect on the latter deficits, and whether there is a difference in brain circuitry in OSA patients with or without co-morbidities."

More information: Ivana Rosenzweig et al, Distinct cognitive changes in male patients with obstructive sleep apnea without co-morbidities, Frontiers in Sleep (2023). DOI: 10.3389/frsle.2023.1097946 , www.frontiersin.org/articles/1 … le.2023.1097946/full

Provided by Frontiers 

Sleep apnea treatment is effective for older people

Illustration of obstruction of ventilation. Credit: Habib M’henni / public domain

Continuous positive airway pressure is effective at treating sleep apnoea in older people, a new study has found.

27 aug 2014--Obstructive sleep apnoea (OSA) is a condition where the walls of the throat relax and narrow during sleep, interrupting normal breathing and causing profound sleepiness. For people with moderate or severe OSA, doctors usually recommend using a continuous positive airway pressure (CPAP) device, which consists of a small pump that delivers pressurised air into the nose through a mask, stopping the throat from closing.

Previous studies have established the benefits of CPAP in middle-aged people with OSA, but until now there has been no research on whether the treatment is useful and cost-effective for older patients.

The new research found that CPAP reduces how sleepy patients feel in the daytime and reduces healthcare costs. The researchers say CPAP should be offered routinely to older patients with OSA, and more should be done to raise awareness of the condition.

The study, published today in Lancet Respiratory Medicine, involved 278 patients aged 65 or over at 14 NHS centres in the UK. It was led by researchers at Imperial College London and the Royal Infirmary of Edinburgh in collaboration with the Medical Research Council Clinical Trials Unit at UCL, and the Universities of Oxford and York. It was funded by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme.

Around 20 per cent of the adult population experiences breathing problems during sleep. In four to five per cent of middle-aged people, these problems lead to sleepiness in the daytime, classified as obstructive sleep apnoea syndrome. The condition is thought to be more common in older people, but the true prevalence is unknown, in part because patients and their relatives may attribute their sleepiness to old age, or older people can compensate by napping. The disease is becoming more common because obesity is a major risk factor.

Professor Mary Morrell, co-principal investigator of the study from the National Heart and Lung Institute at Imperial College London, said: "Sleep apnoea can be hugely damaging to patients' quality of life and increase their risk of road accidents, heart disease and other conditions. Lots of older people might benefit from this treatment. Many patients feel rejuvenated after using CPAP because they're able to sleep much better and it may even improve their brain function."

Patients with sleep apnoea sometimes stop breathing for 30 seconds or longer at night before they wake up and start breathing again. In these pauses, their blood oxygen levels fall.We think low oxygen levels at night might accelerate cognitive decline in old people, and studies have found that sleep apnoea causes changes in the grey matter in the brain. We're currently researching whether treatment can prevent or reverse those changes," said Professor Morrell.

Co-principal investigator Dr.Renata Riha, Consultant and Honorary Reader at the Royal Infirmary of Edinburgh, added that sleep medicine spans many disciplines and comprises an important area of research which deserves support and greater recognition by funding bodies, universities and public policy makers. "Sleep disorders, such as sleep apnoea, impact on a wide variety of chronic conditions, potentially leading to their development or worsening them, including diabetes, heart attacks, strokes and possibly even cancer. Successful treatment diminishes this risk but we still have a great deal of work to do in the area," she said.

More information: A. McMillan et al. 'Continuous positive airway pressure in older people with obstructive sleep apnoea syndrome (PREDICT): a 12-month, multicentre, randomised trial.' Lancet Respiratory Medicine, Published Online 25 August 2014. dx.doi.org/10.1016/S2213-2600(14)70172-9

Provided by Imperial College London

Overactive bladder linked to sleep apnoea in women

Sleep apnoea in women has been linked to overactive bladder syndrome in a new study.

05 sept 2012--The research, presented today at the European Respiratory Society's Annual Congress in Vienna, has provided new evidence suggesting a connection between the two conditions.

Overactive bladder syndrome is characterised by an increased frequency to urinate along with incontinence and frequent awakening periods during night time to use the toilet (nocturia). The need to urinate during the night is also a common symptom of sleep apnoea, but little research has been carried out to investigate any links between the two conditions.

Researchers from the Hospital del Mar in Barcelona, Spain, analysed 72 female patients referred to a sleep disorders clinic with suspected sleep apnoea. All patients completed a questionnaire asking them about four symptoms associated with their bladder control; urgency and frequency of urination, incontinence and nocturia. They were also asked to rate their discomfort with each of these symptoms.

The results from the questionnaires were then analysed and rated on two scales in order to evaluate both the severity of symptoms and discomfort for each of the four variables, scoring from 0 to 3 for each of these four items.

The analysis showed that 62 of the women were diagnosed with sleep apnoea. The people within this group showed significantly higher scores for the prevalence of symptoms associated with bladder control and their discomfort with these symptoms.

Within the group diagnosed with sleep apnoea, the symptoms were rated a median average score of 5, out of a possible total of 12, compared to a score of 3 in the group not diagnosed with the condition. The median average score for discomfort with bladder control symptoms was 4 out of 12, compared with a score of 1 in the group of women who weren't diagnosed with sleep apnoea.

Lead author, Núria Grau from the Hospital del Mar in Spain, said: "Overactive bladder has a prevalence of 16% among people over 40 years in Europe and it is a difficult condition to live with, affecting a person's quality of life. The findings of this study provide evidence that bladder control could be linked to sleep apnoea, although we do not know whether one of the conditions causes the other.

"The next step in our research is to investigate the role of continuous positive airway pressure therapy in these patients and its impact on the symptoms of overactive bladder."

Provided by European Lung Foundation

Among Obese Diabetics, Sleep Apnea May Be Common

23 may 2009-- People who are obese and have type 2 diabetes often have undiagnosed sleep apnea as well, a new study has found.

In fact, of the 306 participants in the study, about 87 percent were found to have sleep apnea but had never been diagnosed with the disorder. The findings appear in the June issue of Diabetes Care.

People in the study, all obese and all with type 2 diabetes, had participated in a sleep study and answered questions about sleep apnea symptoms such as snoring and daytime sleepiness.

More than 30 percent of the study participants had 16 to 20 episodes per hour in which their breathing would stop during sleep, and 22 percent had more than 30 episodes an hour, which is considered severe sleep apnea, according to the researchers.

Most of those who were undiagnosed also had a larger waist circumference, which the researchers found to be significantly associated with sleep apnea, as is higher body-mass index (BMI).

"The high prevalence of undiagnosed and, therefore, untreated sleep apnea among obese patients with diabetes constitutes a serious public health problem," study author Gary D. Foster, director of the Center for Obesity Research and Education at Temple University, said in a school news release.

Sleep apnea increases the risk of heart disease and stroke, according to the release.

"Doctors who have obese patients with type 2 diabetes need to be aware of the possibility of sleep apnea, even if no symptoms are present, especially in cases where the patient has a high BMI or waist circumference," Foster said.

More than a bad night's sleep

Study finds sleep apnea widely undiagnosed among obese type 2 diabetics

22 may 2009--Sleep apnea has long been known to be associated with obesity. But a new study published in the June issue of Diabetes Care finds that the disorder is widely undiagnosed among obese individuals with type 2 diabetes – nearly 87 percent of participants reported symptoms, but were never diagnosed.

For those with untreated sleep apnea, it doesn't just mean their sleep is disrupted; existing research shows that it can also mean an increased risk of heart disease and stroke.

"The high prevalence of undiagnosed, and therefore, untreated sleep apnea among obese patients with diabetes constitutes a serious public health problem," said Gary Foster, PhD, lead author and director of the Center for Obesity Research and Education at Temple University.

The new study, called Sleep AHEAD, looked at 306 obese patients with type 2 diabetes already enrolled in the Look AHEAD trial, a 16-site study investigating the long-term health impact of an intensive lifestyle intervention in 5, 145 overweight or obese adults with type 2 diabetes.

Each participant had a sleep study (polysomnogram) that measures various breathing and brain activity during sleep. Participants also filled out a series of questions about symptoms related to sleep (snoring, sleepiness during the day), and had their weight, height, waist and neck circumferences measured.

Researchers found that 86.6 percent of participants had sleep apnea, yet reported never being diagnosed. More than 30 percent of these had between 16 and 20 episodes per hour where they would stop breathing, and 22 percent had more than 30 episodes per hour, considered severe sleep apnea. Most of these also had a larger waist circumference, which researchers found, along with higher BMI, to be significantly associated with sleep apnea.

Obesity has long been known to be associated with sleep apnea, but researchers say that these findings are alarming.

"Doctors who have obese patients with type 2 diabetes need to be aware of the possibility of sleep apnea, even if no symptoms are present, especially in cases where the patient has a high BMI or waist circumference," said Foster.

Currently, more than half of obese or overweight individuals have diabetes, the seventh leading cause of death in the United States.

###

Other authors on the study were Kelley Borradaile, PhD from Temple University; Mark Sanders, MD, Anne Newman, MD, David Kelley, MD, from the University of Pittsburgh; Richard Millman, MD, Rena Wing, PhD from Brown University; Garry Zammit, MD from Clinilabs; Thomas Wadden, PhD, Valerie Darcey, MS, and Samuel Kuna from the University of Pennsylvania; F. Xavier Pi SUnyer from Columbia University; and the Sleep AHEAD Research Group. Funding was provided by grants from the National Institutes of Health: National Heart, Lung, and Blood Institute and National Institute of Diabetes and Digestive and Kidney Diseases.

Even mild sleep apnea increases cardiovascular risk

26 oct 2008--People with even minimally symptomatic obstructive sleep apnea (OSA) may be at increased risk for cardiovascular disease because of impaired endothelial function and increased arterial stiffness, according to a study from the Oxford Centre for Respiratory Medicine in the UK.
"It was previously known that people with OSA severe enough to affect their daytime alertness and manifest in other ways are at increased risk of cardiovascular disease, but this finding suggests that many more people—some of whom may be completely unaware that they even have OSA—are at risk than previously thought," said lead author of the study, Malcolm Kohler, M.D.
The study will be published in the first issue for November of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.
"Only one out of approximately five subjects with [clinically defined OSA] complains of excessive daytime sleepiness in population studies," wrote Geraldo Lorenzi-Filho, M.D., Ph.D. in an editorial in the same issue of the Journal. "[I]t is now recognized that OSA triggers a cascade of biological reactions, including increased sympathetic activity, systemic inflammation, oxidative stress, and metabolic alterations that are potentially harmful to the cardiovascular system."
To determine the exact nature of some of these effects, Dr. Kohler and colleagues performed a controlled, cross-sectional study to assess differences in endothelial function (often a harbinger for cardiovascular problems to come), arterial stiffness and blood pressure in patients with minimally symptomatic OSA. They compared 64 patients who had proven OSA to matched control subjects without OSA.
Their findings suggested that minimally symptomatic OSA is a cardiovascular risk factor to a degree not previously known.
"In our study, the augmentation index, a measure of central arterial stiffness that independently predicts cardiovascular events in high-risk populations, was significantly higher in patients with minimally symptomatic OSA compared to matched controls," said Dr. Kohler. "We also found impaired endothelial function as indicated by decreased vascular reactivity of their arteries compared to control subjects without OSA."
The difference in arterial stiffness between OSA patients and control subjects, Dr. Kohler said was "comparable in size to the effect seen after four weeks' continuous positive airway pressure (CPAP) therapy in patients with moderate to severe symptomatic OSA."
This suggests that asymptomatic or minimally symptomatic patients with OSA may enjoy a cardiovascular benefit from CPAP therapy.
Dr.Kohler and colleagues from the Oxford Centre for Respiratory Medicine are currently investigating the effects of 6 month CPAP therapy on arterial stiffness and endothelial function as part of an international randomized controlled trial (Multicentre Obstructive Sleep Apnoea Interventional Cardiovascular Trial; MOSAIC) which will show the impact of CPAP therapy on cardiovascular risk in patients with minimally symptomatic OSA.
###
Full Text of Original Article Available Here: http://www.thoracic.org/sections/publications/press-releases/resources/110108Kohler.pdf
Full Text of Original Editorial Available Here: http://www.thoracic.org/sections/publications/press-releases/resources/OSAed110108.pdf

Sleep apnea linked to increased risk of death

02 aug 2008--Sleep-disordered breathing (also known as sleep apnea) is associated with an increased risk of death, according to new results from the Wisconsin Sleep Cohort, an 18-year observational study supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. Researchers found that adults (ages 30 to 60) with sleep-disordered breathing at the start of the study were two to three times more likely to die from any cause compared to those who did not have sleep-disordered breathing. The risk of death was linked to the severity of sleep-disordered breathing and was not attributable to age, gender, body mass index (an indicator of overweight or obesity), or cardiovascular health status.
"Sleep-Disordered Breathing and Mortality: Eighteen-Year Follow-Up of the Wisconsin Sleep Cohort," is published August 1 in the journal Sleep.
Researchers followed 1522 generally healthy men and women for an average of 13.8 years after testing them for sleep-disordered breathing using a standard overnight sleep test. Participants with severe sleep-disordered breathing were three times more likely to die during the study than those without breathing problems during sleep. Those who were not treated were at even greater risk. Participants with untreated severe sleep-disordered breathing were four times more likely to die from any cause and five times more likely to die from cardiovascular conditions.
The Wisconsin Sleep Cohort is the most comprehensive assessment yet of mortality risks associated with sleep-disordered breathing and the first to study a randomly selected population of adults in the United States. The findings suggest that the treatment of severe sleep-disordered breathing may be protective, especially against cardiovascular deaths. Further studies are needed to determine whether the findings are applicable across the United States, and how treatment may improve survival, quality of life, and the overall health status of affected individuals.
Michael J. Twery, PhD, director of the NHLBI National Center on Sleep Disorders Research, is available to comment on these findings, as well as on associated health risks of sleep-disordered breathing, and the importance of diagnosing and treating the condition.
An estimated 12-18 million Americans have moderate to severe sleep-disordered breathing. Periodically during sleep, the upper airway becomes narrowed or blocked, and air has trouble reaching the lungs; in some cases, breathing stops completely (called apnea) for seconds to minutes at a time. The frequent pauses in breathing disrupt sleep and prevent adequate amounts of oxygen from entering the bloodstream. Interruptions in breathing are potentially serious medical conditions and should be evaluated by a physician to determine whether treatment is needed.
Because affected individuals are asleep and typically unaware of the breathing problems, and the condition cannot be diagnosed during routine physician office visits, most people with sleep-disordered breathing are undiagnosed.
Untreated sleep-disordered breathing has been linked to a greater risk of cardiovascular disease and risk factors – including high blood pressure, stroke, and diabetes -- as well as to excessive daytime sleepiness, which can impair quality of life and performance on the job or in school, and increase the risk of injury or death from work-related accidents and vehicular crashes.
Common signs that should be discussed with a physician include complaints of snoring from bed partners, excessive daytime sleepiness, and morning headache. Sleep-disordered breathing occurs in people of all ages, but is more common in men, the elderly, and overweight individuals. With the growing prevalence of overweight and obesity in the United States and the aging population, the number of individuals with sleep-disordered breathing is likely to rise.
###
NOTE: On July 28, 2008, the first joint Scientific Statement on Sleep Apnea and Cardiovascular Disease by the American Heart Association (AHA) and the American College of Cardiology was published online in the Journal of the American College of Cardiology and Circulation. Written in collaboration with the NHLBI National Center on Sleep Disorders Research, the statement describes the types and prevalence of sleep disordered breathing (apnea), and its relevance to individuals who either are at risk for or already have established cardiovascular disease. The committee issued the statement recommending that sleep disordered breathing be evaluated in patients with cardiovascular disease because of the increasing evidence, the widespread prevalence of sleep apnea, and its association with the rising levels of obesity.
For more information:
Sleep apnea, http://www.nhlbi.nih.gov/health/public/sleep/sleep_apnea.htm
Your Guide to Healthy Sleep, http://www.nhlbi.nih.gov/health/public/sleep/healthy_sleep.htm
The National Center on Sleep Disorders Research, http://www.nhlbi.nih.gov/about/ncsdr/index.htm
Part of the National Institutes of Health, the National Heart, Lung, and Blood Institute plans, conducts, and supports research related to the causes, prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood diseases; and sleep disorders. The Institute also administers national health education campaigns on women and heart disease, healthy weight for children, and other topics. NHLBI press releases and other materials are available online at www.nhlbi.nih.gov.
The National Institutes of Health — The Nation's Medical Research Agency — includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

APSS: Sleep Apnea Increases Risk of Death

By Michael Smith
BALTIMORE, 13 june 2008--reathing in sleep causes significant mortality, according to researchers here.In a long-running population-based study in Wisconsin, those with severe sleep-disordered breathing at baseline had a 3.2-fold increase in risk of death from any cause compared with people whose sleep breathing was normal, found Terry Young, Ph.D., of the University of Wisconsin in Madison.During 18 years of follow-up in the study, those with severe sleep-disordered breathing had a mortality rate of 14.6 per 1,000 person-years, compared with 2.85 for those whose sleep breathing was normal, Dr. Young said at SLEEP 2008, the meeting of the Associated Professional Sleep Societies.
"Untreated sleep apnea," Dr. Young concluded, is "significantly associated with increased risk of death."
The Wisconsin Sleep Cohort recruited 1,522 participants, ages 30 through 60, and tested them with overnight polysomnography at baseline and every four years thereafter, Dr. Young said.
They were divided into four groups, based on the apnea-hypopnea index, which divides the number of awakenings per night by the number of hours of sleep.
For this analysis, those with an apnea-hypopnea index below five were considered to be normal, while those from five through 14 were classified as having mildly disordered breathing.
Those from 15 through 19 were said to have moderate sleep-disordered breathing and those 30 or above were classified as severe. Sleep apnea is usually defined as an apnea-hypopnea index of greater than 15.
Using Social Security and Wisconsin death records, the investigators found that after 20,963 person-years of follow-up, 80 of the original cohort had died.
Cox regression analysis, adjusted for body mass index, age and sex, showed that compared to participants with an apnea-hypopnea index below five, the hazard ratio for death from any cause was 3.2 (with a 95% confidence interval from 1.6 to 6.8). The trend over the four groups was significant at P=0.005.
When the 126 participants using continuous positive airway pressure were excluded -- those treated for sleep apnea, in other words -- the hazard ratio for all-cause mortality jumped to 4.3 for the most severely affected and the trend was significant at P<0.001. p="0.03."

In this untreated subgroup, the risk for cardiovascular death was also increased. Compared to those without disordered breathing, those with the most severe apnea had a hazard ratio for cardiovascular death of 5.2. The 95% confidence interval was 1.4 to 19.1 and the trend was significant at P=0.03.
One implication of that analysis is that continuous positive airway pressure may reduce the risk of death in people with severe sleep apnea, Dr. Young said.
Another study reported here supported the notion that sleep apnea increases cardiovascular risk.
Researchers on the MrOS study, whose main goal is to look at osteoporotic fractures in men, conducted in-home polysomnography on 2,905 men with an average age of 76.4 years, according to Katie Stone, Ph.D., of California Pacific Medical Center in San Francisco.
On the basis of the results, they were stratified into those with an apnea-hypopnea index of below 15 and those with an apnea-hypopnea index of 15 or higher. There were 718 cardiovascular events in 2.5 years of follow-up.
Dr. Stone reported that men whose apnea-hypopnea index was 15 or higher had a 2.8-fold increased risk of heart failure compared to those in the lower group (with a 95% confidence interval from 1.4 to 5.4).
Taken together, the two studies confirm the dangers of sleep apnea, according to James Krainson, M.D., of Pulmonary Physicians of South Florida in Miami, who was not involved with either study.
"We always knew it was bad for your health, but the link with mortality hadn't been proved as definitively as now," Dr. Krainson said. "The more data we have, the more we know it's real."
The "clinical lesson" is that more physicians -- especially those in primary care -- need to be aware of the risks of sleep apnea for their patients and to do more to treat them, he said.

Primary source: Associated Professional Sleep Societies meetingSource reference:Stone KL, et al "Sleep disordered breathing and incident cardiovascular events in older men: the MrOS sleep study" APSS Meeting 2008; Abstract 885.

Sleep apnea costly for older adults

Fri Mar 7, 5:22 PM ET
Elderly and middle-aged adults with obstructive sleep apnea may be a bigger drain on healthcare services than their counterparts without the common sleep disorder, new research suggests.
People with obstructive sleep apnea, or OSA, stop breathing for short periods of time during sleep. It occurs when soft tissues in the back of the throat relax and temporarily block the airway. The condition is frequently seen in individuals who are obese and those who snore.
Research has suggested that adults with untreated OSA are high consumers of healthcare resources, investigators report in the Journal of the American Geriatrics Society.
Dr. Ariel Tarasiuk, of Soroka University Medical Center in Beer-Sheva, Israel, and colleagues analyzed healthcare costs among 158 elderly adults, aged 67 to 89 years and 1,166 middle-aged adults who were 40 to 64 years old, during the 2 years prior to being diagnosed with OSA. They compared these costs with those of with age and gender matched controls without the sleep disorder.
The researchers found that healthcare costs were nearly twofold higher among the two sleep apnea groups, compared with the controls. Healthcare costs were also nearly two times higher among elderly sleep apnea patients compared with middle-aged sleep apnea patients, the investigators report.
The higher healthcare costs among elderly OSA patients may be due to cardiovascular illness and the use of psychoactive medications, the researchers say, noting that elderly patients with the highest healthcare costs were more likely to be diagnosed with cardiovascular disease and be taking psychoactive drugs than elderly patients with lesser healthcare costs.
Tarasiuk's team also found that snoring -- a frequent symptom of OSA -- was more common among elderly patients (96.3 percent) than middle-aged patients (88.8 percent). The older group also averaged 25 minutes less sleep a night and more severe episodes of not breathing.
SOURCE: Journal of the American Geriatrics Society, February 2008

Surgery Disparaged as First-Line Treatment for Sleep Apnea

By John Gever
ADELAIDE, Australia, Jan. 4 -- Surgeons should take a pass on uvulopalatopharyngoplasty as first-line treatment for obstructive sleep apnea, researchers here concluded. Several recent meta-analyses and literature reviews found inconsistent benefits and high rates of adverse effects from uvulopalatopharyngoplasty, which is growing in popularity as first-line therapy, according to Adam G. Elshaug, Ph.D., of the University of Adelaide, and colleagues.
"Upper airway surgery should not be first-line treatment for obstructive sleep apnea in adults," they wrote in the Jan. 5 issue of BMJ.
Surgical therapies as first-line treatment should be confined to controlled clinical trials, they added. Continuous positive airway pressure (CPAP) along with weight and alcohol management should remain the preferred initial treatment, with mandibular advancement devices as a second-line choice, they recommended.
Despite little evidence from controlled trials that it works safely among general sleep apnea patients, uvulopalatopharyngoplasty is growing in popularity, Dr. Elshaug and colleagues said.
They analyzed five published systematic reviews, including two they had conducted themselves. None of the reviews found unalloyed benefit for uvulopalatopharyngoplasty.
For instance, a 2005 review by the Cochrane Collaboration of seven randomized trials, with a total of 412 patients, revealed inconsistent results. Only three trials with 225 patients demonstrated significant improvement with polysomnographic recordings following uvulopalatopharyngoplasty. Four studies with 138 patients found improvements in health-related quality of life.
Impact on sleep apnea symptoms was confirmed in only two of the seven trials. "The studies assembled in the review do not provide evidence to support the use of surgery in sleep apnea/hypopnea syndrome, as overall significant benefit has not been demonstrated, and overall significant benefit was not shown," the Cochrane reviewers wrote.
Another review by Scandinavian researchers of 48 mostly nonrandomized studies covering 21,346 patients, published last year, found that as many as 62% of patients had persistent adverse effects. These included dry throat, globus sensation, difficulty in swallowing, voice changes, and disturbances in smell and taste. As many as 22% of patients said they regretted having surgery.
A meta-analysis published in 2007 by the Adelaide group on 18 surgical studies determined that treatment success was "limited." They defined success as post-surgical apnea-hypopnea index scores of five or less.
The analysis found success rates of 13% for phase I procedures including uvulopalatopharyngoplasty (14 studies with 347 patients) and 43% for phase II procedures including osteotomies (four studies with 38 patients).
Akram Khan, M.D., of the University of Florida in Jacksonville, said the 13% figure "is very low."
Dr. Khan reported substantially higher success rates for uvulopalatopharyngoplasty at the American College of Chest Physicians meeting last October.
He found that 24.2% of patients had apnea-hypopnea index scores of five or less after upper airway surgery in a review of 978 patients treated at the Mayo Clinic.
The surgery also had benefits for patients who did not achieve complete success, he added. "Uvulopalatopharyngoplasty also helped lower the CPAP pressure needed by the patients subsequent to surgery," he noted later.
Dr. Khan agreed that uvulopalatopharyngoplasty is not appropriate first-line treatment for everyone with sleep apnea. But for patients in relatively good overall condition, it could be considered, he said.
"An ideal patient for uvulopalatopharyngoplasty is someone who is young, e.g. less than 40, is not very heavy (body mass index less than 32), and has an apnea-hypopnea index less than 40," he said. "If these patients are chosen for surgery their response rate is likely going to be much higher."
Dr. Elshaug and colleagues said about 6% to 7% of people in high-income countries have moderate or severe obstructive sleep apnea, and 20% have mild symptoms.
Successful treatment is important because sleep apnea is associated with a range of morbidities, including car crashes.
Funding sources for the study were not disclosed. Drs. Elshaug and Khan declared no financial conflicts of interest. Two of Dr. Elshaug's co-authors serve as directors of AHTA and ASERNIP-S, organizations that evaluate health technologies including surgical procedures. One consults on health technology assessment for the Australian Government Department of Health and Aging.
Primary source: British Medical JournalSource reference:Elshaug A, et al "Upper airway surgery should not be first line treatment for obstructive sleep apnea in adults" BMJ 2008; 336: 44-45.

Sleep Apnea May Affect the Heart Via Vessels

BUFFALO, N.Y., June 1 -- Endothelial injury may explain in part how obstructive sleep apnea raises cardiovascular risk, according to researchers here.
In a small study, moderate apnea was associated with significantly elevated levels of circulating apoptotic endothelial cells, which in turn were correlated with impaired vasodilation, found Ali A. El Solh, M.D., M.P.H., of the Erie County Medical Center and University at Buffalo here, and colleagues.
However, eight weeks of continuous positive airway pressure (CPAP) treatment improved these measures of vascular function, they reported in the first June issue of the American Journal of Respiratory and Critical Care Medicine.
Obstructive sleep apnea is known to cause vascular dysfunction and increase risk of coronary artery disease more than fourfold and risk of stroke more than eightfold, the researchers noted.
Many mechanisms have been proposed, such as hypoxia reoxygenation, oxidative stress, and release of proinflammatory markers, they wrote, "all of which have been described to cause endothelial cell apoptosis."
"These findings provide an additional mechanism for the predisposition of patients with obstructive sleep apnea to premature vascular disease," they said.
The study included 14 consecutive male patients who had an apnea-hypopnea index of more than five episodes per hour (average 23.7 per hour) verified by polysomnography at a single center.
Also, 10 men without sleep-disordered breathing were recruited from the center's wellness clinic as controls.
All participants were healthy nonsmokers not taking any medications. Baseline characteristics were similar between groups though body mass index tended to be higher in the apnea group (30.6 versus 27.8 kg/m3, P=0.11).
To detect apoptotic endothelial cells, the researchers performed flow cytometry on blood samples from subjects measuring for cells that were positive for expression of both CD146, which "is exclusively expressed on mature endothelial cells," and Annexin V, an early marker of apoptotic cell death.
Baseline flow cytometry showed that apnea patients had twice as many of these cells circulating as controls (39.2 versus 17.8 cells/mL, P<0.001).
Apoptotic endothelial cells in the circulation were correlated significantly with some aspects of sleep apnea. The associations were:
Significant for the apnea-hypopnea index (P=0.004).
Significant for time spent with less than 90% oxygen saturation (P=0.01).
Not significant for the arousal index (P=0.15).
In a univariate analysis, higher levels of apoptotic endothelial cells was moderately associated with impaired vascular function as measured by endothelial-dependent brachial artery dilation (P=0.001).
This impairment is "a precursor of atherosclerosis related events," the investigators said.
After these baseline measurements, the sleep apnea group received nasal CPAP treatment for eight weeks with an average pressure setting of 9.7 mm Hg for an average of 5.2 hours per night.
After treatment, the sleep apnea group had significantly fewer circulating apoptotic endothelial cells (22.3 versus 39.2 cells/mL, P<0.001). All but two apnea patients had a reduction in this marker of vascular damage.
This change was associated with a trend toward improvement in endothelium-dependent vasodilation (P=0.07).
"The profound decrease in circulating apoptotic endothelial cells in patients after CPAP therapy underlines the role of obstructive sleep apnea in the initiation of apoptotic machinery," Dr. El Solh and colleagues wrote.
The mechanism for this effect is not clear, they said.
But, in vitro evidence suggests that endothelial injury or apoptosis causes elevated circulating levels of apoptotic endothelial cells rather than being a result of it, they noted.
Also, more circulating apoptotic endothelial cells would mean less nitric oxide production crucial to artery vasodilatation, they noted, potentially raising the risk of hypertension and acute heart attack.
CPAP likely restores the physiologic function of the lining of the blood vessels, reducing those risks, Dr. El Solh said.
Further research is needed before the results could be used clinically, he added.
Future applications could include using circulating apoptotic endothelial cells could be used "as a novel marker of vascular dysfunction, allowing risk stratification and monitoring of athero-modifying regimens," the researchers wrote.
They cautioned, though, that the findings were limited by lack of thorough assessment to exclude coronary artery disease in study participants.
Excluding women to keep the study population homogeneous means "further investigation is needed to determine whether sex exhibits differential endothelial apoptosis," they added.
They also noted that while the addition of a control group consisting of a parallel group of patients matched for age, sex, and severity of disease who would be denied CPAP treatment. would strengthen the results, it was not feasible. "Given what we know about the increased morbidity and mortality of untreated obstructive sleep apnea, such a design would be problematic."
But the findings likely would be generalizable to women because "it is well known that women, particularly those of reproductive age, have far better flow-mediated dilation responses," Dr. El Solh and colleagues concluded.

Sleep apnea frequent with heart failure

NEW YORK (Reuters Health) - About one quarter of heart failure patients have moderate-to-severe obstructive sleep apnea and they also have significantly higher death rates than those without sleep apnea, Canadian researchers report.
Obstructive sleep apnea is a common problem that typically occurs when soft tissues in the back of the throat temporarily block off airflow during sleep. During sleep, it is not uncommon for patients to have numerous periods of absent breathing lasting for several seconds each. The perpetual lack of adequate sleep can also impair quality of life.
Dr. Hanqiao Wang and colleagues at the University of Toronto in Ontario conducted a study of 164 patients who were referred to the Heart Failure Clinic of Mt. Sinai Hospital between 1997 and December 2004. Standard sleep tests were performed to diagnose sleep apnea.
As reported in the Journal of the American College of Cardiology, the investigators identified 37 patients with untreated moderate-to-severe sleep apnea, 14 patients with treated disease, and 113 without sleep apnea or mild disease that did not require treatment.

Silent Strokes Linked to Sleep Apnea

Obstructive sleep apnea patients have a high rate of silent brain infarctions that can be seen by magnetic resonance imaging, according to researchers here.
They also have elevated levels of biochemical markers associated with cerebrovascular disease, found Kenji Minoguchi, M.D., Ph.D., of Showa University School of Medicine.
On the other hand, treatment with nasal continuous positive airway pressure (nCPAP) over three months reduced the level of disease markers and may lower the risk of disease, Dr. Minoguchi and colleagues said in the second March issue of the American Journal of Respiratory and Critical Care Medicine.
For reasons that could not be explained, the silent brain infarctions had no obvious clinical consequences.
The researchers enrolled 50 men with newly diagnosed obstructive sleep apnea and 15 obese men who had no sleep disorder to serve as controls. None had other co-morbidities.

http://www.medpagetoday.com/Pulmonary/SleepDisorders/tb1/5260

Undiagnosed Sleep Apnea May Be Common in Patients With Pacemakers

A majority of patients with pacemakers in a recent series were found to have previously undiagnosed, predominantly obstructive, and often severe sleep apnea. The incidence reached 68% among those with atrioventricular block as the indication for pacing.
"Systematic screening of these patients should be performed owing to the potential cardiovascular consequences of sleep apnea syndrome," write the study's authors, Stéphane Garrigue, MD, PhD, from University of Bordeaux and Grenoble in Grenoble, France, and associates, who acknowledge that how best to manage sleep apnea in patients with pacemakers remains unclear.
To be practical, any such screening would likely not involve full sleep studies but, rather, would be limited to simpler assessments such as pulse oximetry and nasal flow measurement, according to coauthor Patrick Lévy, MD, PhD, from the University of Bordeaux and Grenoble. In patients with appropriately equipped pacemakers, he told heartwire, sleep apnea syndrome could be revealed by assessment of nocturnal tidal volumes from measurement of transthoracic impedance, a technique previously demonstrated by his group as well as others.
http://www.medscape.com/viewarticle/553591?rss