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Half of hypertensive pregnant women who snore and one quarter of those who do not snore have unrecognized obstructive sleep apnea (OSA), suggesting such women should be tested for this condition. Findings from this cohort study were published online May 29 in BJOG.

OSA is associated with reduced nocturnal blood oxygen levels and other morbidity. The prevalence of OSA increases during pregnancy, affecting up to one third of women by the third trimester.

“We know that habitual snoring is linked with poor pregnancy outcomes for both mother and child, including increased risk of C-sections and smaller babies,” lead author Louise O’Brien, PhD, associate professor, Sleep Disorders Center and Department of Neurology, University of Michigan, Ann Arbor, said in a news release. “Our findings show that a substantial proportion of hypertensive pregnant women have [OSA] and that habitual snoring may be one of the most telling signs to identify this risk early in order to improve health outcomes.”

The study goal was to examine the prevalence of OSA among women with and without hypertensive disorders of pregnancy followed-up at obstetric clinics at an academic medical center. Pregnant women who were normotensive and those with hypertensive disorders (chronic hypertension, gestational hypertension, or preeclampsia) completed a questionnaire regarding habitual snoring. They also underwent overnight ambulatory polysomnography to determine the presence and severity of OSA.

In what is the largest study to date on the association between the two conditions, researchers in Canada demonstrated a link between obstructive sleep apnoea (OSA) – a common breathing disorder that affects people during sleep – and the development of type 2 diabetes.

The team led by Dr Tetyana Kendzerska of the University of Toronto analysed data from 8,678 adults with suspected OSA and without diabetes at baseline who took part in a diagnostic sleep study between 1994 and 2010. All of the participants were tested for OSA and graded according to the severity of their sleep apnoea, based on the number of apnoeas (complete blockage of the upper airway) and hypopnoeas (partial blockage of airway) experienced per hour of sleep, and followed for development of diabetes.

During follow-up, 1,017 (11.7%) of the participants were diagnosed with type 2 diabetes. After adjusting for known risk factors for the disease, including age, sex, BMI, neck circumference and smoking at baseline, those classed as having severe OSA had a 30% greater risk of developing type 2 diabetes compared to those without OSA. Diabetes risk was also 23% higher for patients with mild or moderate OSA. In addition, Rapid eye movement sleep, lack of oxygen in the blood, and activation of the sympathetic nervous system, as indicated by a higher average heart rate during sleep, were linked to higher diabetes risk.

“After adjusting for other potential causes, we were able to demonstrate a significant association between OSA severity and the risk of developing diabetes,” Dr Kendzerska said in a statement. “Our findings that prolonged oxygen desaturation, shorter sleep time and higher heart rate were associated with diabetes are consistent with the pathophysiological mechanisms thought to underlie the relationship between OSA and diabetes.”

The lead author added that the results “address some of the limitations of earlier studies on the connection between OSA and diabetes”, as their study involved a larger sample size and a longer median follow-up. The researchers did, however, acknowledge a few limitations to the study, including not being able to screen for family history of diabetes and ethnicity.

“The OSA-related predictors of increased diabetes risk that we found in our study may allow for early preventative interventions in these patients,” Dr. Kendzerska concluded.

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Both men and women appear to have a greater risk of stroke if they suffer from obstructive sleep apnea, researchers found.

Through up to 14 years of follow-up, stroke risk increased along with the obstructive sleep apnea index to a similar extent in both men and women, according to Suzanne Bertisch, MD, instructor in medicine at Harvard Medical School/Beth Israel Deaconess Medical Center in Brookline, Mass.

The 5-year probability of having a stroke with the least severe obstructive sleep apnea index was 0.4% for women and 0.6% for men, while the probability in the highest quartile of obstructive sleep apnea severity was 1.2% for women and 1.8% for men, she reported at the American Thoracic Society meeting in San Diego.

At 10 years, the probability of having a stroke if you were in the lowest quartile of the sleep apnea index was 0.9% for women and 1% for men, while the probability of having a stroke in the highest quartile of the apnea index was 2.3% in women and 3.1% in men.

All results were adjusted for various confounders, including age, race, education level, smoking status, diabetes, hypertension, and body mass index, she said.

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Sufferers of a common sleep-breathing disorder have diminished activity among neurons responsible for keeping heart rate low, reveals a new study published today [16 May] in The Journal of Physiology.

The research discovered that in obstructive sleep apnoea (OSA), neurons in the brainstem that control heart rate experience a blunting of their activity. The reduction of neuronal activity likely contributes to the increased heart rate, blood pressure and risk of adverse cardiovascular events that occur in patients with OSA.

OSA is a common cardiovascular disease, occurring in 24% of adult males and 9% of adult females, which causes repetitive interruptions of breathing during sleep. Lack of oxygen during these episodes brings the person to a lighter state of sleep or brief wakefulness to restore normal breathing. Cycles of interrupted breathing and arousal from sleep can occur as frequently as once per minute.

Dr David Mendelowitz, who led the study at The George Washington University USA, says:

“Lack of sleep leaves the mind and body tired, leading to poor mental and physical performance, and if untreated OSA increases a person’s risk of developing hypertension and irregular heartbeats. Therefore it is very important that we have discovered some of the underlying mechanisms that could injure the heart and other cardiovascular tissues.

“Our study shows that progression of blunted cardiovascular reflexes is accompanied, and likely maintained by, inhibition of neurons in the brainstem that protect the heart and normally maintain a low resting heart rate. This study would predict that patients who have OSA, and also take sleep medicines, might be at heightened risk for an exaggerated reduction of essential neuronal activity that protects the heart.”

The team explored these mechanisms in rats, by mimicking OSA for four weeks and studying the changes in blood pressure, heart rate, and synaptic activity in parasympathetic neurons that control heart rate.

Future work will need to build from this foundation and focus on finding targets to restore the usual cardio-protective function of these neurons to help reduce the risk of arrhythmias, elevated heart rate, and blood pressure that occur with this disease.

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People with sleep apnea, a common sleep disorder, may be at increased risk for the bone-thinning disease osteoporosis, especially women and older people, a new study suggests.

Sleep apnea causes repeated, brief interruptions in breathing during sleep. Untreated sleep apnea can increase a person’s risk of heart disease, heart attack and stroke.

“Ongoing sleep disruptions caused by obstructive sleep apnea can harm many of the body’s systems, including the skeletal system,” said study co-author Dr. Kai-Jen Tien, of Chi Mei Medical Center in Tainan, Taiwan.

“When sleep apnea periodically deprives the body of oxygen, it can weaken bones and raise the risk of osteoporosis,” Tien said. “The progressive condition can lead to bone fractures, increased medical costs, reduced quality of life and even death.”

For the study, published April 15 in the Journal of Clinical Endocrinology & Metabolism, researchers analyzed the medical records of nearly 1,400 people in Taiwan diagnosed with obstructive sleep apnea between 2000 and 2008. They compared them with more than 20,600 people who did not have the sleep disorder.

Over six years of follow-up, people with sleep apnea were 2.7 times more likely to be diagnosed with osteoporosis. The risk for the bone-thinning disease was highest among women and older people with sleep apnea, according to the study.

“As more and more people are diagnosed with obstructive sleep apnea worldwide, both patients and health care providers need to be aware of the heightened risk of developing other conditions,” Tien said in a journal news release. “We need to pay more attention to the relationship between sleep apnea and bone health so we can identify strategies to prevent osteoporosis.”

However, the study only noted an association between sleep apnea and osteoporosis. It does not prove that one causes the other.

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Sleep apnea is common in people with multiple sclerosis and may contribute to their fatigue, a new study shows. Fatigue is one of the most frequent and debilitating symptoms experienced by MS patients. The study included 195 people with MS who completed a sleep questionnaire and were assessed for daytime sleepiness, insomnia, fatigue severity and sleep apnea.

One-fifth of the patients had been diagnosed with sleep apnea and more than half were found to have an elevated risk for the condition. The researchers also found that sleep apnea risk was a significant predictor of fatigue severity.

MS is a chronic, frequently disabling disease that attacks the central nervous system, according to the National Multiple Sclerosis Society. Symptoms range widely, from mild signs such as numbness in the limbs to severe symptoms including paralysis or loss of vision.

The new findings suggest that sleep apnea may be a common but under-recognized contributor to fatigue in MS patients, and doctors should not hesitate to check these patients for sleep problems, study author Dr. Tiffany Braley, an assistant professor of neurology at the University of Michigan Multiple Sclerosis and Sleep Disorders Centers, said in an AASM news release.

“Obstructive sleep apnea is a chronic illness that can have a destructive impact on your health and quality of life,” and MS patients at high risk for sleep apnea should undergo a comprehensive sleep evaluation, academy president Dr. M. Safwan Badr said in the news release.

The study appears in the Feb. 15 issue of the Journal of Clinical Sleep Medicine, an AASM publication. About 400,000 people in the United States have MS, according to the National Multiple Sclerosis Society. Up to 7 percent of men and 5 percent of women have sleep apnea, according to the AASM.

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A link has already been found between sleep apnea and hypertension but recent research suggests that if people have sleep apnea and hypertension, they should treat sleep apnea first and it will take care of hypertension.

The study involved 194 patients who were diagnosed with hypertension and also suffering from sleep apnea. Some patients were randomly administered CPAP while others were not. The patients continued to take their blood pressure medications.

It was found that those patients who received CPAP showed reduction in their blood pressure. Their average blood pressure of 24 hours was lowered 3.1 mm/Hg more than those who didn’t receive CPAP. Diastolic blood pressure also gets reduced by 3.2 mm/Hg. The study lasted for 12 weeks. At the end of the study, researchers noted that 36% of CPAP receiving patients showed 90% decline in their night time blood pressure as compared to 22% of those who didn’t receive CPAP.

Researchers found that prevalence of sleep apnea in patients who are suffering from hypertension is very high and undergoing from a standard sleep apnea treatment is beneficial for the patient. The further advised that individuals having sleep apnea should undergo sleep study to determine whether they are suffering from constructive sleep apnea.
Further studies are needed to evaluate long term benefits of this treatment.

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It’s well-established that obstructive sleep apnea is linked with increased heart risks. But now, a new study teases apart what exactly it is about the sleep disorder, characterized by pauses in breathing during sleep leading to disrupted sleep, that seems to predict these cardiovascular events.

Obstructive sleep apnea is measured by the number of times a person stops breathing during sleep (the apnea-hypopnea index, or AHI). However, researchers found that there were a number of other elements of sleep apnea that seemed to be predictive of cardiovascular events. The biggest one: the amount of time spent sleeping when the oxygen saturation was below 90 percent.

Other elements associated with a cardiovascular event included heart rate, daytime sleepiness, number of awakenings during the night, sleep time and leg movements, the researchers found. While the apnea-hypopnea index was associated with cardiovascular events when it was looked at by itself, it was no longer considered a significant predictor once all the other elements were factored in.

The study, published in the journal PLOS Medicine, is based on 10,149 people with obstructive sleep apnea who underwent diagnostic polysomnography between 1994 and 2010; 1,172 of those people developed cardiovascular disease.

“We believe a revision of the operative definition of OSA [obstructive sleep apnea] may be necessary, to reflect not simply the frequency of apneas and hypopneas, but the actual physiologic consequences that result — the severity of oxygen desaturation, sleep fragmentation, sleep deprivation and sympathetic activation,” the University of Toronto and St. Michael’s Hospital researchers said in the study. “It is these ‘downstream’ phenomena that we have found to be more predictive of CV [cardiovascular] risk.”

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A new study suggests that patients with spinal cord injuries could benefit from careful assessment for sleep apnoea.

Results show that 77 percent of spinal cord injury survivors had symptomatic sleep-disordered breathing, and 92 percent had poor sleep quality. The study also found that the nature of sleep-disordered breathing in patients with spinal cord injury is complex, with a high occurrence of both obstructive and central sleep apnea events. The occurrence of central sleep apnea, which requires special consideration in diagnosis and treatment, was more common in patients with a cervical injury than in those with a thoracic injury.

“The majority of spinal cord injury survivors have symptomatic sleep-disordered breathing and poor sleep that may be missed if not carefully assessed,” said principal investigator and lead author Dr. Abdulghani Sankari, physician scientist at John D. Dingell VA Medical Center and Wayne State University School of Medicine in Detroit, Mich. “Our findings help in identifying the mechanism of sleep-disordered breathing in spinal cord injury and may provide potential targets for new treatment.”

The study results appear in the Jan. 15 issue of the Journal of Clinical Sleep Medicine, which is published by the American Academy of Sleep Medicine.

“Sleep-disordered breathing may contribute to increased cardiovascular mortality in spinal cord injury patients,” said American Academy of Sleep Medicine President Dr. M. Safwan Badr, who was involved in the study. “All spinal cord injury patients should undergo a comprehensive sleep evaluation using full, overnight polysomnography for the accurate diagnosis of sleep apnea.”

Sankari and his team studied 26 chronic spinal cord injury patients, including 15 with cervical and 11 with thoracic injuries. All subjects had baseline spirometry, a battery of questionnaires and attended polysomnography with flow and pharyngeal pressure measurements.

According to the authors, this is the first study to assess sleep-disordered breathing and ventilation changes comparing two different levels of spinal cord injury — cervical vs. thoracic

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People with sleep apnoea and hard-to-control high blood pressure may see their blood pressure drop if they treat the sleep disorder, Spanish researchers report.

Patients in this study were taking three or more drugs to lower their blood pressure, in addition to having sleep apnoea. Participants who used the CPAP device for 12 weeks reduced their diastolic blood pressure (the bottom number in a blood pressure reading) and improved their overall night-time blood pressure, the researchers found.

“The prevalence of sleep apnoea in patients with resistant [high blood pressure] is very high,” said lead researcher Dr Miguel-Angel Martinez-Garcia, from the Polytechnic University Hospital in Valencia. “This [sleep apnoea] treatment increases the probability of recovering the normal nocturnal blood pressure pattern,” he said.

Patients with resistant high blood pressure should undergo a sleep study to rule out obstructive sleep apnoea, Martinez-Garcia said. “If the patient has sleep apnoea, he should be treated with CPAP and undergo blood pressure monitoring.”

The report, published in the issue of the Journal of the American Medical Association, was partly funded by Philips-Respironics, maker of the CPAP system used in the study. The CPAP system consists of a motor that pushes air through a tube connected to a mask that fits over the patient’s mouth and nose. The device keeps the airway from closing, and thus allows continuous sleep.

Dr Gregg Fonarow, a spokesman for the American Heart Association and professor of cardiology at the University of California, Los Angeles, agrees that most patients with hard-to-control high blood pressure also suffer from sleep apnoea.

“Close to three out of four patients with resistant [high blood pressure] have been found to have obstructive sleep apnoea, and this sleep apnoea may contribute to the difficulty to control the blood pressure in these patients,” he said.

Although this study showed a benefit from CPAP in controlling blood pressure, questions remain about the treatment’s overall effectiveness, Fonarow said.

“Whether these improvements in blood pressure can be sustained in the long term and will translate to improved health outcomes will require additional studies,” he said.

Source: health24

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