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.
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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.
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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.
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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.
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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.
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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.
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MedicalResearch.com Interview with: Nan Hee Kim M.D., Ph.D., Professor
Korea University Ansan Hospital,
Gojan1-dong, Danwon-gu, Gyunggi-do, Korea
MedicalResearch: What is the background for this study? Dr. Nan Hee Kim: Many individuals in modern society experience a discrepancy between social and biological time. Especially during the work or school week, we are often forced to be awake against our preferred time. In addition, the increase of light, TV, computer and internet make people stay up late at night. However, night owls (evening persons) have been reported to have more health and behavioral problems than morning persons. Evening persons experience eating disorders, negative mood and insufficient sleep compared to morning persons. They initiate sleep later in the night but need to wake up earlier than their biologic morning due to social demands. There is abundant evidence that short sleep duration and insomnia are significant risk factors for obesity and diabetes. Therefore, we feel the necessity to reveal whether evening persons are associated with metabolic abnormalities in the general population.
MedicalResearch: What are the main findings?Dr. Nan Hee Kim: In middle-aged adults, people who stayed up late had a 1.7-fold increased risk for type 2 diabetes and metabolic syndrome, and a 3.2-fold increase in risk for sarcopenia as compared with morning persons, independent of sleep duration and lifestyle. Evening persons were associated with reduced muscle mass in men and increased fat mass including visceral fat in women.
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MedicalResearch.com Interview with:
Richard G. Stevens, Ph.D.,
Professor, Cancer Epidemiologist
UConn Health
Medical Research: What is the background for this study? What are the main findings?
Dr. Stevens: Since first introducing the concept of a possible connection between exposure to light at night and breast cancer in the mid-80s, we’ve seen growing evidence of how artificial light can suppress the circadian hormone melatonin and bring about physiological changes.
The extent of this “circadian disruption” varies by the type of light and the time of day. Humans evolved with a body clock that followed the solar clock. Nature intended us to be awake in daylight and at rest in the dark of night. Therefore, the intense, short-wavelength light of the sun in the morning triggers us to become awake and alert, just as the absence of sunlight in the evening allows our body to produce melatonin. Even with the use of fire to provide light in the evening, the circadian impact was relatively minimal because of firelight’s place on the red end of the visible spectrum.
Humans survived under this simple formula for many thousands of years. Then electric light started to take an increasingly strong foothold in everyday life. Today we are typically surrounded at all hours of the day and night by artificial light – in many cases it’s not bright enough during the day to match the sun, and it’s too bright at night to be conducive to the natural sleep/wake cycle. Think computer screens, tablets, smart phones, e-readers, etc. These devices emit enough short-wavelength, or blue, light to disrupt our body clocks in the evening. So do fluorescent and LED lights.
Our paper – I worked with Dr. Yong Zhu from Yale on this – represents a new analysis and synthesis of what we know up to now on the effect of lighting on our health. We don't know for certain, but there's growing evidence that the long-term implications of this may have ties to breast cancer, obesity, diabetes, and depression, and possibly other cancers.
Exposure to electric light started about 130 years ago, which is a tiny period of time in evolutionary terms. In other words, not long enough to undo human evolution. (more…)
MedicalResearch.com Interview with:
David A Kalmbach, PhD
Sleep and Circadian Research Laboratory
Department of Psychiatry
University of Michigan Medical SchoolMedical Research: What is the background for this study? What are the main findings?Dr. Kalmbach: As it happens, my research background is in sexual health, and my clinical work is in behavioral sleep medicine. Therefore, I've long been interested in the intersection between sleep and sexual response, though there has been little research in this area. With the growing recognition of a wide range of morbidities associated with poor sleep, coupled with the multifactorial etiology of sexual dysfunctions, I wanted to investigate whether sleep disturbance was associated with poorer sexual response. Using a 2-week daily diary approach in a sample of 171 young women, we found that longer reported sleep duration led to greater sexual desire the next day. This relationship was mirrored by finding that the likelihood of partnered sexual activity was increased following nights during which women slept longer. We also found an association between genital arousal and sleep length, though this relationship was more complex. Women reported greater vaginal arousal during sexual activity following nights of shorter sleep. However, women who slept longer on average reported better vaginal arousal than women who obtained less sleep on average. This dual relationship may reflect differential effects of a single night of sleep deprivations versus chronic sleep deprivation. However, I think more research is needed to delineate the underlying mechanisms of these relationships. Even so, I think it is notable that daytime sequelae of poor sleep (e.g., mood changes, fatigue) did not account for the relationships between sleep and sexual response.
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MedicalResearch.com Interview with:
Dave Kennaway, PhD Professor
Lloyd Cox Senior Research Fellow,
Head Circadian Physiology Laboratory
School of Paediatrics and Reproductive Health
Robinson Research Institute,
Faculty of Health Sciences, Medical School,
University of Adelaide Australia
MedicalResearch: What is the background for this review? What are the main findings?Dr. Kennaway: There is evidence that melatonin is being prescribed to for sleep disorders in children and adolescents who are developing normally despite the fact that there have been no properly designed studies on the effects of prolonged administration to children. In countries where melatonin has been registered, it is for use as a monotherapy for the short term treatment of primary insomnia, characterised by poor quality of sleep in patients who are aged 55 years and over. Use in Paediatrics is always “off-label”. After more than 50 years of melatonin research in animals there is overwhelming evidence that melatonin administration affects many organ systems. These include important effects on the reproductive organs of rodents, cats, ruminants and primates and melatonin is in fact registered as a veterinary drug for this purpose. The effects of melatonin, however, go beyond the potential reproductive consequences, including effects on cardiovascular, immune and metabolic systems. It is clear that many paediatricians, practitioners and parents are unaware of this.
MedicalResearch: What should clinicians and patients take away from your report?Dr. Kennaway: Clinicians and patients need to recognise that melatonin is a hormone and not a drug developed for a specific purpose or illness. There have been no appropriate trials in children addressing the effects of prolonged administration of melatonin in children. Given the extensive literature on the role of the hormone in normal physiology it is unlikely that such trials would ever be approved. Should endocrine or other abnormalities appear in the future in children previously treated with melatonin it will not be tenable to argue that we were surprised.
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MedicalResearch.com Interview
Professor Nick Franks
Professor of Biophysics and Anaesthetics
Professor William Wisden,
Chair in Molecular Neuroscience
Department of Life sciences
Wolfson Laboratories, Imperial College, South Kensington London
Medical Research: What is the background for this study? What are the main findings?
Profs. Franks and Wisden: We were interested in finding out how a particular type of sedative drug, dexmedetomidine, works in the brain. This drug is increasingly used during intensive care for sedation of patients, but unlike other powerful sedatives, it induces a state whereby the patient can be temporarily woken up. This is a highly useful property because it means patients can be both sedated and responsive during procedures. The drugged sedative state induced by dexmedetomidine struck us as being highly similar to the deep sleep that we all need to have if we have been extensively sleep deprived. If people and animals are kept awake for extended periods of time, they have to sleep. Most people know this from common experience - catching up on lost sleep. But how and why we need to sleep after sleep deprivation is not known. We found that dexmedetomidine-induced sedation and this recovery sleep used the same brain circuits, in a tiny area at the base of the brain called the preoptic hypothalamus. To do this we used a new genetic technique in mice that allowed us to mark or "tag" which neurons in the mouse’s brain were active during sedation or recovery sleep after sleep deprivation. The beauty of this technique is that we could then specifically reactivate these same neurons several days later with a special molecule that only binds to the tagged neurons. This reactivation caused the mice to go into a deep sleep. We concluded that the sedative drug dexmedetomidine copies or hijacks the mechanism used by the brain to respond to sleep deprivation and trigger deep sleep.
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MedicalResearch.com Interview with: Matthew Buman PhD Asst Professor
SNHP Exercise & Wellness
Arizona State University
Medical Research: What is the background for this study? What are the main findings?
Dr. Buman: A lack of physical activity is a known risk factor for insomnia, poor sleep, and obstructive sleep apnea. In addition to physical activity, sedentary behavior has emerged as an important behavior. Sedentary behavior is not just the lack of physical activity, but actually refers to the time someone spend sitting. This behavior has been shown to, independent of physical activity, be related to many poor health outcomes including cardiovascular disease, diabetes, and even premature death. This is the first study to examine whether there is a relationship between excess sitting and insomnia, poor sleep, and risk for obstructive sleep apnea.
We found, after adjusting for physical activity and body weight (among other confounding factors), that total daily sitting was associated with poor sleep quality but not other sleep metrics or OSA risk. However, we also examined sitting while watching television and found a significant relationship between this type of sitting and a host of sleep quality metrics as well as risk for OSA. In a subsequent analysis we found that despite the independent relationship between sitting while watching television with OSA risk, those that were physically active were protected from this negative impact.
(more…)
MedicalResearch.com Interview with:
Katherine M. Keyes, Ph.D.
Assistant Professor of Epidemiology
Columbia University
Mailman School of Public Health
New York, NY 10032
Medical Research: What is the background for this study? What are the main findings?
Dr. Keyes: The Monitoring the Future study is an annually conducted survey of 8th, 10th, and 12th grade high school students in the United States, covering a wide range of adolescent health behaviors. The same questions on adolescent sleep were queried every year since 1991, allowing us to examine historical trends in the amount of sleep adolescents report. We found that there have been substantial decreases in the proportion of adolescents who report 7 or more hours of sleep on a regular basis, across all age groups and across all demographic groups. In the most recent years, after age 15, less than half of adolescents report regularly getting 7 or more hours of sleep every night. Given the importance of sleep in both the short and the long term for adolescent health, these findings suggest substantial public health concern. (more…)
MedicalResearch.com Interview with:
Karen Thorpe PhDProfessor, Developmental Psychology
Program Leader, Early Education and Development Group
Program leader, Sleep in Early Childhood Group
School of Psychology and Counseling
Queensland University of Technology Australia
MedicalResearch: What is the background for this study? Professor Thorpe: Sleep is undoubtedly important not only for how well we think, feel and behave in our daily lives but also for longer-term health. In childhood, the quantity and quality of night-time and 24 hour sleep have consistently been identified as predictor of health. For example, night sleep predicts weight status. These findings have led to the hypothesis that increasing quantity of sleep through promoting daytime sleep would benefit child health. We sought to look for evidence on the independent effects of daytime sleep on child health, learning and behavior to assess whether this hypothesis was supported. (more…)
MedicalResearch.com Interview with:
David S. Black, Ph.D., M.P.H.
Associate Professor of Preventive Medicine
Keck School of Medicine of USC.
Medical Research: What is the background for this study? What are the main findings?
Dr. Black: Sleep disturbances pose a significant medical and public health
concern for our nation’s aging population. An estimated 50% of people
aged 55 years and older suffer from some form of sleep problem,
including initiating and maintaining sleep. Sleep can be affected by a number of things. There are obvious factors like disturbances, dealing with insomnia or any form of aches and pains. But there is also one that many people have probably not considered. Traffic noise. Just like the factors listed previously, there is always a solution to a problem. There isn't anything that cannot be fixed. If you are someone that is having trouble sleeping due to the high level of traffic noises around your area, it may be best to look into a site like soundproofpanda.com to find a solution that can help reduce this issue and eventually provide you with a good's night sleep. Older adults report the highest prevalence of sleep problems compared to younger age groups when quantified by both self-report and biological assessment.
Moderate sleep complaints in older adults are often associated with
deficits in daytime functioning, including elevated levels of fatigue,
disturbed mood such as depressive symptoms and reduced quality of
life, and lead to the onset of clinical insomnia. Addressing moderate
sleep complaints and sleep-related daytime dysfunction using
community-accessible programs is a promising public health approach.
Our main findings indicate that the mindfulness training program,
which is available to the general community, resulted in improvement
in sleep quality at post-intervention relative to a highly active and
standardized sleep hygiene education program. Effect size for
improvement in sleep quality was large (0.89) and of clinical
relevance considering that effect sizes obtained from all types of
behavioral interventions on self-reported sleep quality outcomes
averages 0.76 in older adults. Meta-analyses comparing treatment
modalities indicate that the mean effect size for self-reported sleep
improvements resulting from pharmacotherapy (0.87) (i.e.,
benzodiazepines, benzodiazepine receptor agonists) and behavioral
therapy (0.96) are of medium-to-large magnitude in mixed-age adult
samples with primary insomnia. Thus, our observed changes are
consistent with previous studies and are at the level of a minimally
important difference for insomnia severity. The mindfulness program
also yielded relative improvements on sleep-related daytime
impairments of depression and fatigue symptoms that were of
medium-to-large effect size.
(more…)
MedicalResearch.com Interview with:
Christa Van Dort PhD
Department of Anesthesia, Critical Care, and Pain Medicine,
Department of Brain and Cognitive Sciences,
Picower Institute for Learning and Memory,
Massachusetts General Hospital, Harvard Medical School Boston, MA, 02114
Medical Research: What is the background for this study? What are the main findings?
Dr. Van Dort: Sleep is crucial for survival and maintenance of health. Inadequate sleep and sleep disorders impair many brain and body functions such as executive function, the immune system and memory consolidation. The benefits of sleep are dependent on normal sleep physiology and patterns. Natural sleep is composed of non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep alternating every 90 min in humans. Each stage provides different benefits, for example deep NREM sleep is associated with feeling rested and REM sleep is important for learning. Current sleep aids do not effectively restore normal sleep physiology or timing and as a result do not fulfill the important functions of natural sleep. To develop new strategies for reproducing natural sleep, we aimed to understand each component of sleep (NREM and REM sleep) individually and then in combination. Cholinergic neurons have been hypothesized to control REM sleep for many years but no one had been able to test this directly due to limited methodology. Optogenetics solved this problem by giving us the ability to activate selectively the cholinergic neurons in the pedunculopontine tegmentum (PPT) and laterodorsal tegmentum (LDT).
The primary finding of this study was that cholinergic neurons in the PPT and LDT are sufficient to drive REM sleep from NREM sleep. These cholinergic neurons were important for initiation of REM sleep but not the duration of REM sleep. Understanding REM sleep control is an important first step in reproducing normal sleep patterns and by itself could enhance learning and memory.
(more…)
MedicalResearch.com Interview with:
Michael K. Scullin, Ph.D.
Principal Investigator of the Sleep Neuroscience & Cognition (SNaC) Laboratory and an Assistant Professor of Psychology & Neuroscience Director Sleep Neuroscience and Cognition Laboratory Baylor University
Medical Research: What is the background for this study? What are the main findings?
Dr. Scullin: One of the purposes of sleep in healthy adults is to optimize cognitive functioning. When we lose out on a few hours of sleep we tend not to be able to focus or think as well as when we get enough sleep (typically 8 hours). Even more interesting is that particular aspects of sleep physiology—our deepest levels of sleep known as slow wave sleep and rapid eye movement sleep—are essential to our brain’s ability to take the information that we learn during the day and stabilize those memories so that we can use them in the future.
Sleep quantity and quality change markedly across the lifespan, though there are individual differences in how much one’s sleep changes. Our work was concerned with the possible long-term repercussions of cutting back on sleep and getting lower quality sleep (less slow wave sleep and rapid eye movement sleep). We reviewed approximately 200 scientific articles on this topic and we found that the amount of total sleep and the quality of that sleep is important to cognitive and memory functioning in young adults and middle-aged adults and can even predict how well someone’s cognitive functioning will be decades later. Thus, if you’re sleeping well when you are 40 then you are investing in preserving your mental functioning at age 50.
(more…)
MedicalResearch.com Interview with:
Jacob Nota M.S.
Binghamton Anxiety Clinic
Department of Psychology
Binghamton University
Binghamton, NY 13902
Medical Research: What is the background for this study? What are the main findings?
Response: As psychologists we are interested in helping individuals improve their quality of life and reduce their symptoms. We know that many people, including those with anxiety and mood disorders, are bothered by repetitive negative thoughts that feel like they are out of control. We are always looking for new ways that we might be able to reduce these kinds of symptoms. We are specifically interested in learning more about how sleep relates to psychopathology because an extensive literature documents the cognitive and emotional impact of sleep disruption. Therefore, addressing sleep disruption may be another avenue for us to explore for helping out clients. However, there is relatively little research on the relation between sleep timing and psychopathology compared to that studying the relation between sleep duration and psychopathology, despite previous studies showing that individuals who go to bed later than they want to have more disorders characterized by worry, rumination, and obsessing.
This study collected cross-sectional data (i.e., measuring sleep, worry, rumination, and obsessing all at the same point in time) from a group of 100 young adults at Binghamton University. We looked at measures of worry, rumination, and obsessing as well as a newer measure of the process thought to be shared across these psychological phenomena (repetitive negative thinking). We found that people who sleep for shorter amounts of time and go to bed later also have greater levels of worry, rumination, and obsessing. This is called repetitive negative thinking (RNT). We also found that individuals who are classified as "evening type" (i.e., tend to stay up later and shape their daily activities around this schedule), a trait that is linked to biological circadian rhythms, report significantly greater levels of repetitive negative thinking compared to individuals who are "morning" or neither type (i.e., not strongly morning or evening).
This is one of the first studies to show that repetitive negative thinking is related to both how long you sleep and when you sleep.
(more…)
MedicalResearch.com Interview with:
Michael Nadorff, PhD, Assistant professor
Mississippi State University
Starkville, Miss.
Medical Research: What is the background for this study? What are the main findings?
Dr. Nadorff: A growing literature has found that insomnia symptoms are associated with suicidal behavior, and several studies suggest that this relation may be independent of several different forms of psychopathology. However, little research has examined the role sleep disorders, such as insomnia, play in explaining why known risk factors, such as alcohol use, are associated with suicidal behavior. In our study, we examined whether insomnia symptoms explained a significant portion of the relation between alcohol symptoms and suicide risk. We found that for both men and women insomnia symptoms explained a significant amount of the variance in the relation between alcohol use and suicide risk.(more…)
MedicalResearch.com Interview with: Dr. Jonathan L. Silverberg MD PhD MPH
Assistant Professor in Dermatology, Medical Social Sciences and Preventive Medicine
Northwestern University, Chicago, Illinois
Medical Research: What is the background for this study? What are the main findings?
Dr. Silverberg: Chronic itch related to childhood eczema has been shown to cause worsened sleep quality with shorter sleep duration, more frequent and prolonged awakening, and overall lower sleep efficiency. However, little is known about the sleep disturbances that occur in adults with eczema.
(more…)
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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:
