MedicalResearch.com Interview with:
Yingting CaoPhD Candidate
Population Research and Outcome Studies
School of Medicine, Faculty of Health Sciences
The University of Adelaide
Freemasons Foundation Centre for Men’s Health
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: As sleep complains have reached a public concern, increasing number studies have investigated it. Most studies focused on the adverse effect of short sleep or poor sleep quality on health but fewer looked it the other way around. Laboratory studies have suggested the potential role of diet in regulating sleep, however, it has not been confirmed in population studies. So, we examined whether dietary factors are associated with sleep in a large cohort of middle-aged and older men in Adelaide, focusing on their sleep, as well as general health including chronic conditions. In this particular paper, we focused on macronutrient intake (we focused on nutrients and food levels in other papers) and sleep.
The main finding was that comparing with the lowest 25% fat intake (mean 58g/d), people in the highest 25% of fat intake reported more daytime sleepiness and had increased number of sleep apnea during the night.
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MedicalResearch.com Interview with:
Anne G. Wheaton, Ph.D.
Epidemiologist
Centers for Disease Control and Prevention
National Center for Chronic Disease Prevention and Health PromotionDivision of Population Health
Epidemiology and Surveillance Branch
Atlanta, GA 30341-3717MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Wheaton: Unintentional injury, mostly from motor vehicle crashes, is the leading cause of death for adolescents. Adolescents who do not get enough sleep are at an increased risk for motor vehicle crashes and other unintentional injury, such as sports injuries and occupational injuries. We evaluated the association between self-reported sleep duration on an average school night and several injury-related risk behaviors (infrequent bicycle helmet use, infrequent seatbelt use, riding with a driver who had been drinking, drinking and driving, and texting while driving) among more than 50 thousand US high school students.
The likelihood of each of five injury-related risk behaviors (infrequent bicycle helmet use, infrequent seatbelt use, riding with a driver who had been drinking, drinking and driving, and texting while driving) was significantly higher for students sleeping ≤7 hours on an average school night compared with 9 hours. Infrequent seatbelt use, riding with a drinking driver, and drinking and driving were also more likely for students sleeping ≥10 hours compared to 9 hours on an average school night. Although short and long sleep may simply be associated with other adolescent risk behaviors, insufficient sleep may cause individuals to take more risks and disregard the possibility of negative consequences. However, the study was cross-sectional, meaning the students were asked questions at one time point, so it is not possible to determine if there is a cause and effect association between sleep and these risk behaviors. Insufficient sleep may contribute to injury risk directly by slowing reaction time, impairing ability to pay attention, or causing a driver to fall asleep, but these results provide evidence that some of the increased risk associated with insufficient sleep might be due to engaging in injury-related risk behaviors.
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MedicalResearch.com Interview with:
Stefanos N. Kales, MD, MPH, FACP, FACOEM
Associate Professor, Harvard Medical School &
Harvard TH Chan School of Public Health
Director, Occupational Medicine Residency
Division Chief OEM, Cambridge Health Alliance
MedicalResearch: What is the background for this study? Dr. Kales: Up to 20% of all large truck crashes are due to drowsy or fatigued driving, which would account for almost 9,000 fatalities and up to 220,000 serious injuries. OSA is the most common medical cause of excessive daytime sleepiness or fatigue, and has been linked with negative impacts on attention, working memory, vigilance, and executive functioning. Past studies primarily of passenger car drivers have linked untreated OSA with a several-fold increased risk of motor vehicle accidents. They have also shown that effective treatment with CPAP reduces this risk close to that of unaffected drivers.
Although commercial truck drivers undergo a biennial examination to determine their medical fitness to safely operate a vehicle, there are currently no mandatory standards for OSA screening or diagnosis, in part because there have been no large-scale studies evaluating the crash risk of commercial drivers diagnosed with OSA.
Our study examined the results of the first large-scale employer program to screen, diagnose, and monitor OSA treatment adherence in the U.S. trucking industry(more…)
MedicalResearch.com Interview with:
Jonathan ShawMD, FRACP, FRCP (UK), FAAHMS
Associate Professor
Domain Head, Population Health Research
Baker IDI Heart and Diabetes InstituteMelbourne VIC 3004
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Shaw: Over the last decade or so, there has been a lot of research connecting obstructive sleep apnoea with type 2 diabetes. They co-exist very frequently in the same individual, they are both much more common in overweight and obese people than in people of healthy weights, both improve with weight loss, and both are associated with other conditions such as hypertension and heart disease. In addition, there has been evidence that some of the key abnormalities occurring in sleep apnoea (in particular, fragmented sleep and intermittent low oxygen levels) may have a direct effect on glucose metabolism, and increase blood sugar levels. This led many people to suspect that untreated sleep apnoea might be one reason that type 2 diabetes is hard to control, and that treating sleep apnoea in people with type 2 diabetes would improve their blood sugar control.
We, therefore, undertook a large trial among people with type 2 diabetes, and previously unrecognised sleep apnoea, in which participants were randomised to either a group receiving specific treatment for sleep apnoea (continuous positive airways pressure, or CPAP, therapy at night) or to a control group.
Over the six months of the trial, we saw no benefit of CPAP therapy in regard to blood sugar control (as measured by HbA1c). Even when we looked at sub-groups with worse blood sugar control at the start or worse sleep apnoea or who did the best in terms of using CPAP every night, there was still no sign of benefit on blood sugar control. We did, however, see some other benefits of CPAP therapy, with less daytime sleepiness, improvements in quality of life and lower diastolic blood pressure.
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MedicalResearch.com Interview with:
Alice Gregory PhD
Department of Psychology
Goldsmiths, University of London
London, UK
Medical Research: What is the background for this study? What are the main findings?
Dr. Gregory: Sleep paralysis involves a total inability to move just as someone is falling asleep or waking up. This experience typically ends within seconds to minutes and is not usually a sign of any wider problem – yet it can be extremely frightening. This is in part because this experience is often accompanied by hallucinations.
To understand what is happening during episode of sleep paralysis it is useful to understand that there are different stages of sleep. One distinction is between Rapid Eye Movement (REM) and Non-Rapid Eye Movement (NREM) sleep. During REM sleep the body is paralysed. Dreaming often occurs during REM sleep, so it has been proposed that this paralysis keeps us safe, by preventing us from ‘acting out our dreams’. During an episode of sleep paralysis, someone may have woken up but has retained certain features of REM sleep (specifically the paralysis and sometimes dream-related hallucinations).
While sleep paralysis is rather common and the public seem incredibly interested in learning more about this, it is surprising that there is such little research on this topic.
Certain risk factors for sleep paralysis have been proposed previously, such as experiencing stress. However, those suffering from this experience are keen for more information, which is currently unavailable. For this reason, we wanted to see whether we could identify other factors which were associated with sleep paralysis.
Furthermore, in reviewing the literature, we were stunned that while it seems obvious that genetic differences between people are likely to be important in explaining why certain people experience sleep paralysis and others do not – there was almost no work on this topic. We decided to investigate this further as well.
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MedicalResearch.com Interview with:Donald A. Wilson, Ph.D.
Professor, Departments of Child & Adolescent Psychiatry and Neuroscience & Physiology
NYU Langone Medical Center
Senior Research Scientist
Nathan Kline Institute for Psychiatric Research
Medical Research: What is the background for this study? What are the main findings?Dr. Wilson: Fetal alcohol spectrum disorder (FASD) is characterized by cognitive, emotional and behavioral problems that are life-long. Generally, it is assumed that the initial trauma of alcohol exposure at a critical time in life is the cause of these problems. In this study using an animal model of FASD, we find that developmental alcohol causes a life-long disturbance in sleep. Given that sleep is important for memory and emotion, among other things, this suggests that developmental alcohol can produce a daily insult to the brain, far outlasting that initial exposure. Each night, the brain is unable to store memories, adjust emotional circuits, remove waste products, in the way that it should, because FASD has disrupted sleep.
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MedicalResearch.com Interview with:
Helen J. Burgess, Ph.D.
Professor, Departments of Behavioral Sciences & Internal Medicine
Director, Biological Rhythms Research Laboratory
Director, Center for Clinical Chronobiology
Rush University Medical Center
Chicago IL 60612Medical Research: What is the background for this study? What are the main findings?Dr. Burgess: The 24 hour circadian clock in the brain has a profound influence on mental and physical health. Circadian rhythm sleep disorders occur when the internal circadian clock’s timing is out of synch with the external social world, which often dictates when we should eat, work and sleep. One such disorder, delayed sleep phase disorder, occurs when the circadian clock runs too late relative to social time.
Patients with delayed sleep phase disorder can appear to simply have insomnia, but careful measurement of their circadian timing can reveal the underlying circadian cause. Also, the treatment of delayed sleep phase disorder with either bright light and/or melatonin can be optimized by knowing a patient’s circadian timing, because the effect of these treatments can vary widely depending on when they are administered.
A problem in the sleep and circadian field is that the gold standard marker of circadian timing in humans, the dim light melatonin onset (DLMO), is typically only measured in the clinic or laboratory. Many clinics do not even measure the DLMO. Our group recently developed a home saliva collection kit to assist people in measuring their DLMO at home. Previously, we found the home DLMOs compared very well to laboratory DLMOs in healthy controls. In this paper, we extended this work to show the kit also works well in patients with delayed sleep phase disorder.
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MedicalResearch.com Interview with: Dr. Yanping Li
Research Scientist
Harvard T.H.Chan School of Public Health
Boston, MA 02115
Medical Research: What is the background for this study? What are the main findings?
Dr. Li: Sleeping difficulty is a common disorder but always lack of attention from both the patients and physicians. Our study finds that women with sleeping difficulty is associated with a higher risk of type 2 diabetes.
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More on Sleep on MedicalResearch.comMedicalResearch.com Interview with:Marie-Pierre St-Onge, Ph.D, FAHA
Assistant Professor, Department of Medicine
New York Obesity Nutrition Research Center
Institute of Human Nutrition
College of Physicians & Surgeons, Columbia University
New York, NY 10032 Medical Research: What is the background for this study? What are the main findings?Dr. St-Onge: We have shown that sleep affects food intake: restricting sleep increases energy intake, particularly from fat (others also find increased sugar intake). We wanted to know if the reverse was also true: does diet affect sleep at night?
Medical Research: What should clinicians and patients take away from your report?Dr. St-Onge: Diet quality can play an important role in sleep quality. Sleep can be affect after only a single day of poor dietary intakes (high saturated fat and low fiber intakes). It is possible that improving one’s diet can also improve their sleep.
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More on Sleep Research on MedicalResearch.com
MedicalResearch.com Interview with:
Dr. Andrew Lim MD, FRCPC
Assistant Professor Neurology
Sunnybrook Health Sciences Centre
Toronto, ON
Medical Research: What is the background for this study? What are the main findings?
Dr. Lim: Our group had previously shown that sleep fragmentation is associated with an increased risk of dementia and cognitive decline. However, there were gaps in what we knew about underlying brain changes that may link sleep fragmentation with these neurological outcomes. Experiments in mice and other animals suggested that damage to blood vessels may be one potential mechanism.
In this study of 315 older individuals who had their sleep measured using wrist-watch like accelerometers, we found that individuals who had the most fragmented sleep were also more likely to have more severe damage to brain blood vessels and blood-vessel related brain injury at death.
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MedicalResearch.com Interview with:
Sunil Sharma MD, FAASM
Associate Professor of Medicine
Director, Pulmonary Sleep Medicine
Associate Director, Jefferson Sleep Disorders Center
Thomas Jefferson University and Hospitals
Philadelphia, PA 19107
Medical Research: What is the background for this study? Dr. Sharma: Congestive heart failure (CHF) is the most common cause of hospital admission and readmissions in United States. More health care dollars are spent on CHF than any other diagnosis. A large chunk of this cost is due to hospital admission. An estimated 50% of the CHF patients are readmitted within 6 months of discharge. The recent Protection Affordable Care Act (ACA) imposes penalties on hospitals for readmissions within first 30-days. It is therefore imperative to find ways to impact the natural history of the disease.
Sleep disordered breathing is a common disorder associated with CHF. It is estimated that up to 70% of the patient with CHF may have SDB. Studies have shown that untreated SDB can worsen CHF and treatment of Sleep disordered breathing has been shown to improve heart function (ejection fraction).(more…)
MedicalResearch.com Interview with:
Prof. Bor-Luen Chiang
Vice Superintendent, National Taiwan University Hospital
Professor of Graduate Institute of Clinical Medicine and Pediatrics
National Taiwan University
Attending Physician, Department of Medical research
National Taiwan University Hospital and
Yung-Sen Chang, MD MPH
Attending physician, Department of Pediatrics,
Taipei City Hospital Renai Br.
Adjunct Attending Physician, Department of Pediatrics
National Taiwan University Children’s Hospital
Adjunct Instructor, School of Medicine, National Yang-Ming University
Medical Research: What is the background for this study?
Prof. Chang: Sleep disturbance is a common disorder in the children with atopic dermatitis (AD) (reported in 47 to 60%), but no effective way of managing this problem had been established. In our preceding study, we found that lower nocturnal melatonin level was significantly associated with sleep disturbance in the patients with AD. Melatonin is a hormone secreted by the pineal gland which plays an important role in sleep regulation. In addition to sleep-inducing effects, melatonin also has anti-inflammatory and immunomodulatory properties which might be helpful for the management o fatopic dermatitis. Furthermore, melatonin has an excellent safety profile with minimal adverse effects, making it a good choice for children. Therefore, we aimed to evaluate whether melatonin is effective for improving the sleep problems and the dermatitis severity in children with atopic dermatitis.
Medical Research: What are the main findings?
Prof. Chang: From our double-blind, placebo-controlled crossover study, we found that after melatonin treatment, the sleep onset latency shortened by 21.4 minutes compared with placebo (from a mean of 44.9 minutes to 21.6 minutes). The Scoring Atopic Dermatitis Index (higher scores representing more severe dermatitis) also decreased by 9.9 compared with placebo (from a mean of 49.1 to 40.2). No adverse events were reported throughout the study.
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MedicalResearch.com Interview with:
Sabine Plancoulaine, MD, PhD
Senior Researcher
NSERM, UMR1153 Epidemiology and Statistics Sorbonne Paris Cité Research Center (CRESS), early Origin of the Child's Health And Development (ORCHAD) Team,
Villejuif, France; and
Paris Descartes University, Paris, France
Medical Research: What is the background for this study?
Dr. Plancoulaine: A decrease in children’s total sleep duration has been reported in the last decades, suggesting that more and more children are now in chronic sleep debt. There is now accumulating evidence that insufficient quantity and/or quality of sleep have a negative impact on children’s physical and mental health development, cognitive function, behaviour and academic success. Sleep disorders and short sleep duration in childhood have also been suggested as predictors of sleep disorders and short sleep duration in adolescence and adulthood. An increased risk of obesity has been shown among shorter sleeper children, especially boys.Medical Research: What are the main findings?
Dr. Plancoulaine: In our study we aimed at describing sleep duration in 3 years old children from a French pre-birth cohort (546 boys and 482 girls) and at investigating gender-specific factors associated with shorter sleep duration defined as <12h/24h.
In our study, children aged 3 years slept on average 12hrs35 and 91% of them were napping. Parental presence when falling asleep (e.g. holding hands) was the only factor associated with shorter sleep duration in both gender and increased the risk by around 3 and 4 in boys and girls respectively.
The other associated risk factors were more gender-specific. Among boys, each hour of TV viewing duration increased by 72% the risk of being a short sleeper and each additional standard deviation of BMI increased the risk by 31%. Among girls, adherence to a fruit and vegetables dietary pattern divided the risk of being short sleeper by 2 while being cared at home increased it by 2.5 folds.
Other investigated factors were not associated (i.e. familial incomes, parental educational level, maternal age at birth, maternal pre-pregnancy BMI, maternal depression status (at birth and at 3y), gestational age, child’s birth rank, birth weight and physical activities at 3y, existence of night awakenings at 3y).
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MedicalResearch.com Interview with:
Mike C Parent, Ph.D.
Assistant Professor, Counseling Psychology
Texas Tech University
Medical Research: What is the background for this study? What are the main findings?
Dr. Parent: There is some research out there on energy drinks, and we know a few things about them. For instance, although the drinks are marketed as though they are for extreme sports athletes, most people who drink them are not athletes. It seems as though drinking them makes some men feel as though they are a part of that extreme sports culture, without even needing to participate in the sports, though. The other part was that, clinically, you would be amazed at how many young men present at student counseling centers and university medical centers with "sleep problems." Then, when you ask them about what they eat and drink during a day, it turns out that some of them are guzzling half a dozen of these drinks a day, or drinking them at night, totally unaware of the extremely high caffeine content. It's true that energy drinks can help people focus a but better or work out a bit harder--but that's because the active ingredient is caffeine. In this research, we aimed to marry together those two lines of work--how does wanting to be more masculine impact energy drink use, and what consequences might energy drink use have for something as basic as sleep hygiene?
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MedicalResearch.com Interview with:
Miklos Z Molnar, MD, PhD, FEBTM, FERA, FASN
Associate Professor of Medicine
Division of Nephrology, Department of Medicine
University of Tennessee Health Science Center
Memphis, TN, 38163
Medical Research: What is the background for this study? What are the main findings?
Response: Restless legs syndrome is a common sleep disorder, but there is a paucity of large cohort studies examining the association of restless legs syndrome with clinical outcomes, including all-cause mortality, incident coronary heart disease, stroke and chronic kidney disease.
From a nationally representative prospective cohort of over 3 million US veterans [93% male, median follow-up time of 8.1 years (interquartile range: 7.0–8.5years)] with baseline estimated glomerular filtration rate ≥60 mL/min/1.73 m2, a propensity-matched cohort of 7392 patients was created, and the association between incident restless legs syndrome and the following was examined:
(1) all-cause mortality;
(2) incident coronary heart disease;
(3) incident strokes; and
(4) incident chronic kidney disease defined as estimated glomerular filtration rate <60 mL/min/1.73 m2.
Compared with restless legs syndrome-negative patients, incident restless legs syndrome was associated with 88% higher mortality risk [hazard ratio and 95% confidence interval: 1.88 (1.70–2.08)], and almost four times higher risk of coronary heart disease and stroke [hazard ratio: 3.97 (3.26–4.84) and 3.89 (3.07–4.94), respectively]. The risk of incident chronic kidney disease was also significantly higher in incident restless legs syndrome patients [hazard ratio: 3.17 (2.74–3.66)] compared with restless legs syndrome-negative counterparts. These associations was independent from other confounders such as demographic data, comorbidities and other sleep disorders (sleep apnea and periodic limb movements in sleep).
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MedicalResearch.com Interview with:
Ana C. Krieger, MD, MPH, FCCP, FAASM
Medical Director, Center for Sleep Medicine
Associate Clinical Professor
Departments of Medicine, Neurology and Genetic Medicine
Weill Cornell Medical College - Cornell University
Associate Attending
NewYork-Presbyterian Hospital
Rockefeller University Hospital
Medical Research: What is the background for this study? What are the main findings?Dr. Krieger: For many years, sleep researchers have been concerned about sleep deprivation in adolescents. Our study shows that high school students have shorter sleep duration on the nights following the spring Daylight Saving Time adjustment. This sleep loss was associated with a decline in daytime vigilance and cognitive performance on the week following DST.
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MedicalResearch.com Interview with:
Markus Jansson-Fröjmark PhD
Associate professor, clinical psychologist
Department of Psychology
Stockholm University
Medical Research: What is the background for this study? What are the main findings?
Response: There is ample evidence suggesting that how people regulate their emotions might influence several types of psychopathology, including anxiety and mood disorders. The purpose of our longitudinal investigation was therefore to examine the association between emotion regulation and how insomnia develops over time. Our main finding was that people whose ability to regulate their emotions had diminished were more likely to develop insomnia and that it was more likely to be persistent. A reduced ability to regulate emotions was associated with an 11% increased risk of developing a new bout of insomnia or reporting persistent insomnia. For anyone that has to deal with insomnia on a daily basis, they may find that is can effect a large part of their lives. Sleep is important for even, as it allows us all to function properly throughout the day. When it comes to Insomnia, there is medication out there that people can take that may help them with this issue. A popular method of treatment is through the use of medical marijuana. If this is something that you have been planning on trying, you would need to obtain your medical marijuana card in Cincinnati (if you live in this city) before you could start receiving product. Hopefully this will help with your insomnia and provide you with a better quality of sleep.
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MedicalResearch.com Interview with:
Chan-Won Kim, M.D.
Clinical Associate Professor
Center for Cohort Studies
Kangbuk Samsun Hospital
Sungkyunkwan University School of Medicine
Seoul, South Korea
Medical Research: What is the background for this study?
Dr. Chan-Won Kim: In modern society, inadequate sleep either in quantity or in quality is a common problem and widely recognized as a potential determinant of adverse health outcomes including cardiovascular health. Very long or very short duration of sleep are associated with an increased risk for clinical cardiovascular events such as coronary heart disease and strokes. In these previous studies, however, it was possible that extreme sleep duration or poor sleep quality was a consequence of previous co-morbidities such as depression and obesity, and it was still unclear if these co-morbidities were really responsible for the effects of sleep disturbances. Therefore, we evaluated the association of sleep duration and quality with early markers of subclinical arterial disease in asymptomatic apparently healthy men and women.
Medical Research: What are the main findings?
Dr. Chan-Won Kim: In our study, we found that sleep duration had a U-shaped association with two early markers of vascular disease. Both short and long sleep duration were associated with a greater amount of calcification in the coronary arteries, a very good measure of subclinical atherosclerosis that predicts the risk of a heart attack. We also found a similar pattern of association with arterial stiffness, a marker of vascular aging. For both markers, we found the lowers risk in study participants who reported 7 hours of sleep. In addition, poor subjective sleep quality was also associated with these markers of vascular disease. Few studies had explored these associations before, and they were inconsistent partly because of small sample sizes. Our research also indicates that these associations were present irrespective of traditional risk factors such as hypertension, hypercholesterolemia, or diabetes.
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MedicalResearch.com Interview with:
Charlotte Lund Rasmussen
Research Unit, Department of Palliative Medicine
Bispebjerg Hospital, Copenhagen, Denmark
Medical Research: What is the background for this study? What are the main findings?
Response: We see that patients with advanced cancer often suffer from fatigue, pain, depression, insomnia and other symptoms, which can have a profound impact on quality of life. Melatonin is a neurohormone and its secretion is closely tied to the circadian rhythm making it a regulator of the sleep-cycle.
Studies have shown that cancer patients have lower levels of melatonin than healthy controls, which may contribute to their fatigue and lowered quality of life. Furthermore, previous studies have found a possible effect of melatonin in cancer therapy, and non-clinical trials have shown melatonin to inhibit cell division in tumors.
To our knowledge, no trials to date have investigated the effects of melatonin on fatigue. Given the role of melatonin in the sleep cycle, the lowered levels of melatonin noted among cancer patients, and results from previous studies, we wanted to investigate melatonin’s effect on fatigue among patients with advanced cancer.
The primary objective of our study was to determine whether oral melatonin administered at night would reduce physical fatigue in patients with advanced cancer who were being treated in a palliative care facility. The effect of melatonin on other cancer-related symptoms including mental fatigue, insomnia, pain, emotional function, loss of appetite, and overall QoL were also investigated.
In this trial we tested a dose of 20 mg of melatonin taken orally at night.
However, melatonin did not improve physical fatigue in patients with advanced cancer. Furthermore, we were unable to identify improvements in any other cancer-related symptoms.
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MedicalResearch.com Interview with:
Stephanie J. Crowley, Ph.D.
Assistant Professor
Biological Rhythms Research Laboratory
Department of Behavioral Sciences
Rush University Medical Center
Chicago, IL 60612
Medical Research: What is the background for this study? Dr. Crowley: Your readers may have seen recent reports by the American Academy of Pediatrics and the CDC about problems with early morning school bells for teens and the need to push school start times later. These recent calls for later school start times come from data showing that biological processes make it challenging for a teen to get enough sleep and be rested for school when they have to wake up very early for school. One of these biological processes is the circadian timing system, which is the approximate 24-hour brain clock that regulates the timing of sleep and wake. During the teen years, the brain clock is shifted later making it more difficult for many teens to fall asleep early enough to get sufficient sleep on school nights.
Medical Research: What are the main findings?
Dr. Crowley: Melatonin suppression, as tested in this new study, is a good indication of how light affects the circadian system. Our findings show that even a very small amount of light (similar to “romantic mood lighting”) in the evening suppressed melatonin levels in the middle-school-aged adolescents. Because evening light “seen” by the brain clock shifts the clock later in time, the message is that biologically-driven later sleep times starts at this early age and needs to be considered when managing school and sleep schedules.
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MedicalResearch.com Interview with:
Helene Benveniste, MD, PhD
Professor of Anesthesiology and Radiology
Vice Chair for Research, Department of Anesthesiology
Stony Brook Medicine, Stony Brook NY
Medical Research: What is the background for this study?
Dr. Benveniste: The ‘glymphatic’ pathway is a part of the brain and is responsible for removal of waste products and excess fluid that built up especially during wakefulness. The concept was introduced by Nedergaard’s team in 2012 from University of Rochester. Importantly it has been shown to remove waste products such as soluble amyloid beta and tau protein which build up excessively in the brain of subjects afflicted with Alzheimer’s disease. The glymphatic system has been studied in detail in animal models (not yet humans) and actually is a brain-wide pathway which runs along (i.e. on the outside) of all vessels in the brain and connects to the space around the brain cells (referred to as the interstitial fluid (ISF) space). The outer part of the glymphatic network ‘tube’ is bordered by a certain type of brain cells so-called ‘astroglial’ cells which are arranged in a special way so that their endfeet cover >97% of the surface of all brain vessels. One can think of this as if the astroglial cell’s ‘endfeet’ are arranged as a donut shaped tube around all the vessels. On the astroglial endfeet there are special water channels (aquaporin-4 water channels) which are critical for how efficiently the glymphatic system can get rid of waste because it allows water to move fast through the brain tissue so as to ‘flush’ waste products out efficiently. The small gap between the astroglial endfeet also act like a ‘sieve’ so that only waste products of a certain size can access the entire pathway. Cerebrospinal fluid (CSF) circulates into the glymphatic pathway from the surface of the brain along the arteries which dives directly from the surface into the deeper part of the brain; and ultimately enters the space around the brain cells; and sweeps through it and thereby mixes with the interstitial fluid of the brain which contains waste products. The CSF-ISF mix with the waste products is then flushed out on the other ‘side’ along the veins and ultimately ends up in lymph vessels in the body and then in the blood.
It has been shown that the glymphatic pathway removes brain waste more efficiently in a state of ‘unconsciousness’ e.g. sleep or anesthesia when compared to wakefulness. Given this intriguing finding i.e. that sleeps seems to affect the waste clearance from the brain we thought that the next to look at was sleeping positions. We did these studies in anesthetized rodents.
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MedicalResearch.com Interview with:
Jonathan Cedernaes M.D., Ph.D.Department of Neuroscience
Uppsala University Sweden
Medical Research: What is the background for this study? What are the main findings?
Dr. Cedernaes: Previous studies have demonstrated that experimental sleep loss and simulated shift work (i.e. misalignment of circadian rhythms) reduces energy expenditure and insulin sensitivity, providing links to why sleep loss may increase the risk of e.g. type-2 diabetes and obesity. Such phenotypes have also been observed in animals in which clock genes are ablated. Clock genes regulate the circadian rhythms of all cells and variants in these have also been associated with increased risk of obesity, insulin resistance and type-2 diabetes in humans. Almost no study has however investigated whether overnight wakefulness - mimicking a situation which recurrently occurs in shift work - can affect the expression of such clock genes in metabolically important tissues, i.e. adipose tissue and skeletal muscle, in humans. Such gene expression changes may both acutely and more long-term be regulated by changes in methylation, i.e. an epigenetic change, which have been found in blood of e.g. shift workers and in e.g. adipose tissue of type-2 diabetic subjects. However, whether sleep loss can lead to epigenetic changes has been unknown, and therefore also whether this could affect genes important for metabolism, such as the core clock genes which are essential for orchestrating and synchronizing downstream metabolic processes according to our circadian rhythms.
With this background in mind, I and associate professor Christian Benedict set out to conduct a study to investigate how one night of sleep loss altered gene transcription and methylation of core clock genes in adipose tissue and skeletal muscle, and whether this would be reflected at the systemic level by an impaired glucose tolerance test in healthy young individuals.
For the study, we had 15 participants undergo two almost 2-day long sessions in our lab, with the first night of each session serving as a baseline or habituation night, with a normal sleep period. On the second night, in random order, participants slept a full night (8.5 hours) in one session, and were kept awake the entire night while being bed-restricted in the other of two sessions. After each of these conditions, we took biopsies in the fasting condition from the subcutaneous adipose tissue and the skeletal muscle.
In collaboration with researchers from the Karolinska Institute, Gothenburg University and the German Institute of Human Nutrition, we were able to observe transcriptional repression of clock genes in the muscle, but not in the adipose tissue following sleep loss compared with normal sleep. Instead, we found methylation of regulatory elements of clock genes to be increased in the adipose tissue but not the skeletal muscle following sleep loss compared with normal sleep. Finally, we observed that participants had an impaired glucose tolerance test when they had been kept awake as compared with their response after sleep. (more…)
MedicalResearch.com Interview with:
Kimberly Allen PhD, RN Assistant Professor
Center for Narcolepsy, Sleep and Health Research
Department Women Children and Family Health Science
Chicago, IL 60612
Medical Research: What is the background for this study? Dr. Allen: Pediatric traumatic brain injuries (TBI) are a leading cause of morbidity and mortality worldwide.Each year in the United States over 1Ž2 million children are admitted to the hospital for traumatic brain injuries (TBIs). Depending on the severity of the injury and how the individual child responds to the primary injury, a range of medical care may be necessary from an overnight hospital admission for observation to admission in the intensive care unit (ICU) and inpatient rehabilitation facility to re-teach and help to recover skills children once knew. The short- and long-term consequences of traumatic brain injuries include: motor and sensory impairments; cognitive, emotional, psychosocial impairments; headaches, and sleep disruptions.
Medical Research: What are the main findings?
Dr. Allen: The main finding from this pilot study with two groups with 15 children in each group: one of children with traumatic brain injuries and one of typically, developing healthy children was that children with traumatic brain injuries have significantly more daytime sleepiness and worse sleep quality compared to the control group. Additionally, children with TBI also had lower overall functional scores (e.g, school, social) compared to the controlled children. All of the surveys were completed by the child’s parent.
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MedicalResearch.com Interview with:
Dr David Cunnington
Sleep Physician & Director
Melbourne Sleep Disorders Centre
East Melbourne Australia
Medical Research: What is the background for this study? What are the main findings?
Response: Insomnia is a very common problem with 15-20% of adults having chronic insomnia, that is, trouble getting to sleep or staying asleep most days for 3 months or more. The most commonly used treatment is sleeping pills or hypnotics, however, they don’t address the underlying disorder, and come with potential side effects. Also, sleeping tablets just mask the symptoms, and as soon as tablets are stopped, symptoms recur. People with chronic insomnia think and behave differently around sleep, which perpetuates their symptoms. The key to improving symptoms in the long run is addressing thoughts and behaviours around sleep, which is what cognitive behaviour therapy does.
Our study showed that cognitive behaviour therapy reduced the time taken to get to sleep by 20 minutes and reduced the amount of time spent awake after falling asleep by nearly 30 minutes. These effects were maintained out to 12 months after treatment. These reductions in time taken to get to sleep and time spent awake are similar to those reported in clinical trials of hypnotics. (more…)
MedicalResearch.com Interview with:
Alexander W. Pastuszak, MD, PhD
Male Reproductive Medicine and Surgery
Scott Department of Urology
Jason Malcolm Scovell
Medical Student, Ofc SA-BCM StudentsBaylor College of MedicineHouston, TX
Medical Research: What is the background for this study? What are the main findings?
Response: Sleep quality is an important component of overall health, and can both exacerbate health issues and be impaired by health problems. Shift workers, primarily those who do not work standard daylight shifts, are prone to sleep problems, a significant concern in light of the fact that up to 25% of the U.S. workforce is comprised of shift workers. As men age, the prevalence of Lower Urinary Tract Symptoms (LUTS), which include urgency, frequency, waking up at night to urinate, and difficulties with urination, increases. Unsurprisingly, men with LUTS report poor sleep in part due to awakening repeatedly during the night. We studied a group of male shift workers, who we believe to be an ‘at-risk’ population, and found that not only do the men who report worse sleep quality have worse Lower Urinary Tract Symptoms, but also men who report difficulty falling asleep have more severe LUTS than those who do not. This latter point is significant, given that most men with LUTS can fall asleep without difficulty, but then awaken repeatedly throughout the night, and suggests that sleep difficulties in this population may be resulting in Lower Urinary Tract Symptoms rather than LUTS exclusively resulting in sleep difficulties.
(more…)
MedicalResearch.com Interview with:
Hans P.A. Van Dongen, Ph.D.
Director, Sleep and Performance Research Center
Research Professor, College of Medical Sciences
Washington State University Spokane, Spokane, WA
On behalf of the authors: Paul Whitney PhD, John Hinson PhD, Melinda Jackson PhD, Hans Van Dongen PhDMedicalResearch: What is the background for this study? What are the main findings?Research: Our main interest is in better understanding why people sometimes are able to manage perfectly well with sleep loss, while at other times sleep loss can have profoundly negative effects. We found that sleep deprivation reduces the effectiveness of signals used to tell when you are right or wrong, an effect we labeled feedback blunting.
Subjects in the study performed a decision making task that was simple but required feedback, i.e., a signal indicating the response was correct or incorrect, to perform correctly. We found that people who were sleep deprived were no longer able to use the feedback information to make correct responses. And when people had to adapt to unexpected changes in when to respond, sleep deprived people were completely unable to adapt to these changing circumstances.
The finding of feedback blunting in this study indicates that people who are sleep deprived not only have trouble sustaining attention to details in the environment (a well established effect of sleep loss), they also have trouble changing the focus of attention to deal with changing circumstances.
An interesting paradox in the research literature has been that people have been shown in many circumstances to perform complex tasks at a very high level while sleep deprived. Yet, we know from real-world experience that sleep deprived people can make catastrophic, life-threatening decisions that they would never have made if they were well rested. The current study is the first to shed light on this issue. It showed that sleep deprived people who get feedback, telling them that their actions are not effective, are less capable of changing their behavior.
The study is part of a line of research in which we are trying to identify how sleep loss changes specific components of cognition, and how these changes may lead to serious problems in everyday life activities. Being able to study and understand these effects of sleep deprivation under controlled conditions is an important step toward preventing human error under real world conditions.
(more…)
MedicalResearch.com Interview with:
Jaime L. Tartar PhD
Behavioral Neuroscience Major Chair Division of Social and Behavioral Sciences
Nova Southeastern University
Fort Lauderdale, FloridaMedical Research: What is the background for this study? What are the main findings?
Dr. Tartar: We set out to understand how poor sleep quality can influence emotion processing. Our rationale for this study was that although sleep perturbations are known to impair cognitive performance, it is not currently clear how poor sleep alters emotion processes. However, given that poor sleep quality is closely associated with the development of mood disorders, it is important to understand how sleep quality affects emotional functioning. We specifically examined the possibility that poor sleep quality creates a cognitive bias in memory and interpretation for emotionally negative stimuli. This would result in maladaptive emotional experiences- for example, through enhanced memory for emotionally negative events (which is also a common characteristic of depression). The idea that negative cognitive bias occurs with poor sleep quality is also consistent with the finding that sleep loss increases sensitivity to emotional stimuli as well as increases undesirable mood states like irritability, anger, and hostility. It is particularly noteworthy that sleep perturbations result in increased emotionality since sleep perturbations are shown to result in a decrease in non-emotional cognitive processes (attention and memory). In order to clarify the role of sleep quality on emotion processing, we tested the relationship between sleep quality and a negative cognitive bias through the use of an emotional memory task. We also aimed to contrast these findings with performance on a non-emotional attention task since sleep impairments have previously been shown to cause impairments in (non-emotional) sustained attention. An interesting feature of the study was that we also accounted for potential confounding effects of stress sensitivity and chronotype (ones preferred time of day) since these are both factors known to be related to sleep quality. We found that, compared to those who reported good subjective sleep quality, participants who reported poor subjective sleep quality showed a negative cognitive bias towards emotionally negative stimuli. Also in agreement with previous work, we show that poor sleep quality has a negative effect on affective symptom measures- poor sleep quality relates to increased depressive symptoms, greater state and trait anxiety, and higher total mood disturbance (increased tension, fatigue, confusion and less vigor). Consistent with previous findings, we also found that subjective sleep quality was related to a decrease in performance on a sustained attention task. Although previous research suggests that stress sensitivity and chronotype would be important variables to consider in the impact of sleep perturbations on emotion processing, we did not find any stress, chronotype, or time of testing effects on these measures.
(more…)
MedicalResearch.com Interview with: Matthias Eikermann, MD, PhD
Associate Professor of Anaesthesia, Harvard Medical School
Director of Research, Critical Care Division
Massachusetts General Hospital
Medical Research: What is the background for this study? What are the main findings?Dr. Eikermann: Obstructive sleep apnea occurs in about 5% of pregnant women, worsens as pregnancy progresses and is likely to persist into the early postpartum period. A main cause of anesthesia-related maternal death is postpartum airway obstruction. We observed among early postpartum women, that 45° upper body elevation increased upper airway diameter and mitigated sleep apnea, without adverse effects on quality of sleep after delivery.
(more…)
MedicalResearch.com Interview with:
Josée Savard, Ph.D.
School of Psychology, Laval University
Cancer Research Center
Quebec City, Quebec, Canada
MedicalResearch: What is the background for this study? What are the main findings?Dr. Savard: This paper reports on a secondary analysis of an 18-month longitudinal study initially conducted in 962 patients about to receive surgery for various types of cancer. The main results of this larger study indicated that insomnia is a significant problem in cancer patients. More precisely, it was found to affect up to 59% of patients at the peri-operative period. In addition, 32% of patients who were good sleepers developed insomnia symptoms at some point during the study (Savard et al., 2009; Savard et al., 2011).
The goal of this particular analysis was to determine the role of cancer treatments and their side effects in triggering/aggravating insomnia symptoms during the 18-month follow-up. Study participants completed questionnaires assessing insomnia severity and somatic symptoms at baseline, as well as 2, 6, 10, 14 and 18 months later. This analysis was conducted separately in women treated for breast cancer (n=465) and men treated for prostate cancer (n=263). In breast cancer patients, chemotherapy and radiation therapy, but not hormone therapy, were found to be associated with increased insomnia severity. This deleterious effect appeared to be due to a number of side effects (e.g., nausea, night sweats, urinary symptoms). In prostate cancer patients, androgen-deprivation therapy was associated with aggravation of insomnia, an effect that was mainly due to the occurrence of night sweats.
(more…)
MedicalResearch.com Interview with:
Carolina P B Gracitelli, M.D.
Ophthalmology - PhD Candidate/ Research Fellow
University of California San Diego - Hamilton Glaucoma Center
Medical Research: What is the background for this study? What are the main findings?
Dr. Gracitelli: Of all the diseases that can lead to blindness, glaucoma is one of the most important diseases; it affects more than 70 million people worldwide, of whom approximately 10 % are bilaterally blind. Different studies have reported that the damage caused by glaucomatous disease lead to retinal ganglion cell (RGC) loss and consequently loss of intrinsically photosensitive retinal ganglion cells (ipRGCs), which is a subtype of retinal ganglion cell. This subpopulation of RGC is clearly related with non-image-forming visual function such as photic synchronization of circadian rhythms and the pupillary light reflex. However, the true impact of glaucoma on sleep quality, sleep disturbance or circadian rhythm was until nowadays controversial.
The main clinical finding of our study was that glaucoma leads to retinal ganglion cell death, including ipRGC death. These cells are connected to several non-image-forming functions, including circadian photoentrainment and pupillary reflexes. Therefore, the image-forming and non-image-forming visual systems are associated with glaucoma. Circadian function has not been well investigated in clinical daily practice, but it can interfere with the quality of life of these patients. Concerns about sleep disturbances in glaucoma patients should be incorporated into clinical evaluations.
(more…)
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