HealthMedicine 10

Findings Reveal Brain Mechanisms at Work During Sleep

Oct. 16, 2012 —
Science Daily/Society for Neuroscience
New findings presented today report the important role sleep plays, and the brain mechanisms at work as sleep shapes memory, learning, and behavior. The findings were presented at Neuroscience 2012, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news about brain science and health.

One in five American adults show signs of chronic sleep deprivation, making the condition a widespread public health problem. Sleeplessness is related to health issues such as obesity, cardiovascular problems, and memory problems.

Today's findings show that:

Sleepiness disrupts the coordinated activity of an important network of brain regions; the impaired function of this network is also implicated in Alzheimer's disease (Andrew Ward, abstract 909.05).
Sleeplessness plays havoc with communication between the hippocampus, which is vital for memory, and the brain's "default mode network;" the changes may weaken event recollection (Hengyi Rao, PhD, abstract 626.08).
In a mouse model, fearful memories can be intentionally weakened during sleep, indicating new possibilities for treatment of post-traumatic stress disorder (Asya Rolls, abstract 807.06).
Loss of less than half a night's sleep can impair memory and alter the normal behavior of brain cells (Ted Abel, PhD, abstract 807.13).

Other recent findings discussed show:

How sleep enables the remodeling of memories -- including the weakening of irrelevant memories -- and the coherent integration of old and new information (Gina Poe, PhD).
The common logic behind seemingly contradictory theories of how sleep remodels synapses, aiding cognition and memory consolidation (Giulio Tononi, MD, PhD).
"As these research findings show, we cannot underestimate the importance of a good night's sleep," said press conference moderator Clifford Saper, PhD, MD, from the Harvard Medical School, an expert on sleep and its deprivation. "Brain imaging and behavioral studies are illuminating the brain pathways that are blocked or contorted by sleep deprivation, and the risks this poses to learning, memory, and mental health."
http://www.sciencedaily.com/releases/2012/10/121016132115.htm

 

Chronic Fatigue Syndrome: System Under Stress

Nov. 14, 2012 —
Science Daily/University of New South Wales
Australian researchers have discovered for the first time that reduced heart rate variability -- or changes in heart beat timing -- best predicts cognitive disturbances, such as concentration difficulties commonly reported by people with chronic fatigue syndrome (CFS). This adds to the growing body of evidence linking autonomic nervous system imbalance to symptoms of this poorly understood disorder.

Chronic fatigue syndrome is characterised by medically unexplained, disabling fatigue and neuropsychiatric symptoms of at least six months' duration. The disturbance underlying the symptoms in CFS is still poorly understood.

"We have studied autonomic function in CFS for some time and our findings clearly indicate a loss of integrity in stress-responsive neural and physiological systems in CFS. Patients with this condition are hyper-responsive to challenges arising both from within the body and from the environment," says lead researcher, Associate Professor Ute Vollmer-Conna of the University of New South Wales in Sydney, Australia.

"Even when they sleep, their stress-responsive neural systems are on high alert, signalling that it is not safe to relax. I think this condition may be understood by analogy to post-traumatic stress disorder, just that in CFS the original trauma is most likely a physiological, internal one, such as a severe infection."

In a study of 30 patients with CFS and 40 healthy individuals, UNSW researchers recorded the heart beats of participants (via ECG) and analysed cardiac responses to cognitive challenges, and associations with mental performance outcomes.

The patients with CFS performed with similar accuracy, but they took significantly longer to complete the tests than people without the condition. They also had greater heart rate reactivity; low and unresponsive heart rate variability; and prolonged heart rate-recovery after the cognitive challenge.

Resting heart rate variability (an index of vagus nerve activity) was identified as the only significant predictor of cognitive outcomes, while current levels of fatigue and other symptoms did not relate to cognitive performance.

"This is the first demonstration of an association between reduced cardiac vagal tone and cognitive impairment in CFS. Our findings confirm previous reports of a significant loss of vagal modulation, which becomes particularly apparent when dealing with challenging tasks. The current results are consistent with the notion that CFS represents a 'system under stress'," Associate Professor Vollmer-Conna says.

The findings could lead to new ways to improve cognitive difficulties in people with CFS, including biofeedback assisted retraining of autonomic functioning, the researchers say.
http://www.sciencedaily.com/releases/2012/11/121115133806.htm

Exposure to Light at Night May Cause Depression, Learning Issues

Nov. 14, 2012 —
Science Daily/Johns Hopkins
For most of history, humans rose with the sun and slept when it set. Enter Thomas Edison and colleagues, and with a flick of a switch, night became day, enabling us to work, play and post cat and kid photos on Facebook into the wee hours.

According to a new study of mice led by a Johns Hopkins biologist, however, this typical 21st-century scenario may come at a serious cost: When people routinely burn the midnight oil, they risk suffering depression and learning issues, and not only because of lack of sleep. The culprit could also be exposure to bright light at night from lamps, computers and even iPads.

"Basically, what we found is that chronic exposure to bright light -- even the kind of light you experience in your own living room at home or in the workplace at night if you are a shift worker -- elevates levels of a certain stress hormone in the body, which results in depression and lowers cognitive function," said Samer Hattar, a biology professor in the Johns Hopkins University's Krieger School of Arts and Sciences.

Published in the Nov. 14 advance online publication of the journal Nature, the mice study demonstrates how special cells in the eye (called intrinsically photosensitive retinal ganglion cells, or ipRGCs) are activated by bright light, affecting the brain's center for mood, memory and learning.

But the study involved mice, so why are we talking about humans? Hattar offers some insight: "Mice and humans are actually very much alike in many ways, and one is that they have these ipRGCs in their eyes, which affect them the same way," he said. "In addition, in this study, we make reference to previous studies on humans, which show that light does, indeed, impact the human brain's limbic system. And the same pathways are in place in mice."

The scientists knew that shorter days in the winter cause some people to develop a form of depression known as "seasonal affective disorder" and that some patients with this mood disorder benefit from "light therapy," which is simple, regular exposure to bright light.

Hattar's team, led by graduate students Tara LeGates and Cara Altimus, posited that mice would react the same way, and tested their theory by exposing laboratory rodents to a cycle consisting of 3.5 hours of light and then 3.5 hours of darkness. Previous studies using this cycle showed that it did not disrupt the mice's sleep cycles, but Hattar's team found that it did cause the animals to develop depression-like behaviors.

"Of course, you can't ask mice how they feel, but we did see an increase in depression-like behaviors, including a lack of interest in sugar or pleasure seeking, and the study mice moved around far less during some of the tests we did," he said. "They also clearly did not learn as quickly or remember tasks as well. They were not as interested in novel objects as were mice on a regular light-darkness cycle schedule."

The animals also had increased levels of cortisol, a stress hormone that has been linked in numerous previous studies with learning issues. Treatment with Prozac, a commonly prescribed anti-depressant, mitigated the symptoms, restoring the mice to their previous healthy moods and levels of learning, and bolstering the evidence that their learning issues were caused by depression.

According to Hattar, the results indicate that humans should be wary of the kind of prolonged, regular exposure to bright light at night that is routine in our lives, because it may be having a negative effect on our mood and ability to learn.

"I'm not saying we have to sit in complete darkness at night, but I do recommend that we should switch on fewer lamps, and stick to less-intense light bulbs: Basically, only use what you need to see. That won't likely be enough to activate those ipRGCs that affect mood," he advises.
http://www.sciencedaily.com/releases/2012/11/121114133921.htm

 

Stress Management Counseling in the Primary Care Setting Is Rare

Nov. 19, 2012 —
Science Daily/Beth Israel Deaconess Medical Center
While stress may be a factor in 60 to 80 percent of all visits to primary care physicians, only three percent of patients actually receive stress management counseling, say researchers at Beth Israel Deaconess Medical Center.

Nerurkar and colleagues examined data from the 2006 to 2009 National Ambulatory Medical Care Survey involving more than 34,000 office visits and 1,263 physicians. They were looking for evidence of doctors who provided stress management help, which included counseling at the visit, providing "information intended to help patients reduces stress through exercise, biofeedback, yoga, etc.," or referrals "to other health professionals for the purpose of coping with stress."

What they found is that stress management counseling by physicians rarely happens in the primary care setting. Just three percent of physicians offer stress counseling, mostly for their more complex patients, particularly those coping with depression.

"Our research suggests that physicians are not providing stress management counseling as prevention, but rather, as a downstream intervention for their sickest patients," says Nerurkar. "Considering what we know about stress and disease, this clearly points to missed opportunities."

The researchers also found that stress management counseling was associated with longer office visits.

"We know that primary care physicians are overburdened. With the volume of patients they see, there simply may not be enough time to provide stress management counseling during the office visit," says senior author, Gloria Yeh, MD, MPH, Director of the Integrative Medicine Fellowship Program at Harvard Medical School and BIDMC. "The fact that we found that so few physicians are counseling their patients about stress supports this, and highlights the need to rethink how primary care is being delivered."

A key step towards incorporating stress management counseling into primary care may be restructuring primary care delivery and payment to support team-based care.

"New payment models designed to promote wellness will enable team-based primary care practices to add counseling and coaching staff to address stress, mental illness and behavioral change more effectively," says co-author, Russell S. Phillips, MD, Director of the Harvard Medical School Center for Primary Care.

These changes could help shift counseling to earlier in the disease process.

"Our findings make us wonder whether stress management counseling, if offered earlier to more patients as prevention, could lead to better health outcomes," says Nerurkar, "But more research is needed to establish the role that stress management might play clinically."

In addition to Nerurkar, Yeh and Phillips, co-authors include Asaf Bitton, MD, MPH and Roger B. Davis, ScD of Beth Israel Deaconess Medical Center.

Nerurkar is supported by an Institutional National Research Service Award from the National Institutes of Health. Davis is supported in part by the Harvard Catalyst and the Harvard Clinical and Translational Science Center.
http://www.sciencedaily.com/releases/2012/11/121119163258.htm

 

Extended Sleep Reduces Pain Sensitivity

December 1, 2012
Science Daily/American Academy of Sleep Medicine
A new study suggests that extending nightly sleep in mildly sleepy, healthy adults increases daytime alertness and reduces pain sensitivity.

"Our results suggest the importance of adequate sleep in various chronic pain conditions or in preparation for elective surgical procedures," said Timothy Roehrs, PhD, the study's principal investigator and lead author. "We were surprised by the magnitude of the reduction in pain sensitivity, when compared to the reduction produced by taking codeine."

Results show that the extended sleep group slept 1.8 hours more per night than the habitual sleep group. This nightly increase in sleep time during the four experimental nights was correlated with increased daytime alertness, which was associated with less pain sensitivity.

In the extended sleep group, the length of time before participants removed their finger from a radiant heat source increased by 25 percent, reflecting a reduction in pain sensitivity. The authors report that the magnitude of this increase in finger withdrawal latency is greater than the effect found in a previous study of 60 mg of codeine.

According to the authors, this is the first study to show that extended sleep in mildly, chronically sleep deprived volunteers reduces their pain sensitivity. The results, combined with data from previous research, suggest that increased pain sensitivity in sleepy individuals is the result of their underlying sleepiness.
http://www.sciencedaily.com/releases/2012/12/121201085915.htm

 

Significant Link Found Between Daytime Sleepiness and Vitamin D

Dec. 14, 2012 —
Science Daily/American Academy of Sleep Medicine
A new study suggests that there is a significant correlation between excessive daytime sleepiness and vitamin D, and race plays an important factor.

Results show that in patients with normal vitamin D levels, progressively higher levels of daytime sleepiness were correlated inversely with progressively lower levels of vitamin D. Among patients with vitamin D deficiency, sleepiness and vitamin D levels were associated only among black patients. Surprisingly, this correlation was observed in a direct relationship, with higher vitamin D levels associated with a higher level of sleepiness among black patients.

"While we found a significant correlation between vitamin D and sleepiness, the relationship appears to be more complex than we had originally thought," said David McCarty, MD, the study's principal investigator. "It's important to now do a follow-up study and look deeper into this correlation."

The study, appearing online in the Dec. 15 issue of the Journal of Clinical Sleep Medicine, involved a consecutive series of 81 sleep clinic patients who complained of sleep problems and nonspecific pain. All patients eventually were diagnosed with a sleep disorder, which in the majority of cases was obstructive sleep apnea. Vitamin D level was measured by blood sampling, and sleepiness was determined using the Epworth Sleepiness Scale.

According to the authors, this is the first study to demonstrate a significant relationship between sleepiness and vitamin D. They noted that it is logical for race to affect this relationship because increased skin pigmentation is an established risk factor for low vitamin D.

The study was not designed to examine causality. However, the authors' previous and current research suggests that suboptimal levels of vitamin D may cause or contribute to excessive daytime sleepiness, either directly or by means of chronic pain.
http://www.sciencedaily.com/releases/2012/12/121214190947.htm

 

Dopamine Regulates the Motivation to Act, Study Shows

Jan. 10, 2013 —
Science Daily/Asociación RUVID
The widespread belief that dopamine regulates pleasure could go down in history with the latest research results on the role of this neurotransmitter. Researchers have proved that it regulates motivation, causing individuals to initiate and persevere to obtain something either positive or negative.

The neuroscience journal Neuron publishes an article by researchers at the Universitat Jaume I of Castellón that reviews the prevailing theory on dopamine and poses a major paradigm shift with applications in diseases related to lack of motivation and mental fatigue and depression, Parkinson's, multiple sclerosis, fibromyalgia, etc. and diseases where there is excessive motivation and persistence as in the case of addictions.

"It was believed that dopamine regulated pleasure and reward and that we release it when we obtain something that satisfies us, but in fact the latest scientific evidence shows that this neurotransmitter acts before that, it actually encourages us to act. In other words, dopamine is released in order to achieve something good or to avoid something evil," explains Mercè Correa.
http://www.sciencedaily.com/releases/2013/01/130110094415.htm

 

Depression After Heart Attack: Threat Perception Has to Be Addressed

Jan. 14, 2013 —
Science Daily/Université du Luxembourg
"Survivors of heart attacks are three times more likely to develop depression during the first six months after their heart attack, than people with no heart disease. If left untreated this contributes to a worse prognosis, for instance further cardiac events and possibly death.

The causes for this high prevalence of depression after heart attacks are still unclear," said Prof. Claus Vögele, Professor of Clinical and Health Psychology at the University of Luxembourg and lead author of the publication entitled "Cardiac Threat Appraisal and Depression after First Myocardial Infarction."

Thirty-six cardiac patients were interviewed five to fifteen days after their first heart attack, six to eight weeks later, and again six months later. They were questioned on their level of fatigue, general health, disease-specific symptoms, work, and family. Depression levels were assessed with questionnaires and clinical diagnoses were established using a structured, clinical interview. To investigate their individual ways of coping with this experience, patients were questioned on rumination, affiliation seeking, threat minimisation, information seeking, and seeking meaning in religion.

The findings are among the first to show that the way patients think about their heart attack has an immediate effect on the likelihood of developing depression. For example, if they continue to perceive their heart attack as a serious threat then they are more likely to experience depression, even weeks after the attack. On the other hand, if patients have ways to focus their thoughts on their recovery and know how to ask for support from their friends and family, then this risk for depression is much reduced.

"These results can be used to help patients to have a more positive outlook on life, even after such a dramatic and life-threatening event," said Prof. Vögele, who is head of a research group on Self-regulation and Health at the University of Luxembourg. "Psychological interventions in the immediate time after the infarct, for instance during the first two weeks, may protect patients from developing depression, and thereby contribute to a smooth recovery."
http://www.sciencedaily.com/releases/2013/01/130114092517.htm

 

Reviewing Alcohol's Effects On Normal Sleep

Jan. 22, 2013 —
Science Daily/Alcoholism: Clinical & Experimental Research
Sleep is supported by natural cycles of activity in the brain and consists of two basic states: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. Typically, people begin the sleep cycle with NREM sleep followed by a very short period of REM sleep, then continue with more NREM sleep and more REM sleep, this 90 minute cycle continuing through the night. A review of all known scientific studies on the impact of drinking on nocturnal sleep has clarified that alcohol shortens the time it takes to fall asleep, increases deep sleep, and reduces REM sleep.

"This review has for the first time consolidated all the available literature on the immediate effects of alcohol on the sleep of healthy individuals," said Irshaad Ebrahim, medical director at The London Sleep Centre as well as corresponding author for the study.

The onset of the first REM sleep period is significantly delayed at all doses and appears to be the most recognizable effect of alcohol on REM sleep, followed by a reduction in total night REM sleep.

"One consequence of a delayed onset of the first REM sleep would be less restful sleep," said Idzikowski. "The first REM episode is often delayed in stressful environments. There is also a linkage with depression."
http://www.sciencedaily.com/releases/2013/01/130122162236.htm

 

Circadian Rhythms Can Be Modified for Potential Treatment of Disorders

Jan. 22, 2013

Science Daily/UC Irvine-

UC Irvine-led studies have revealed the cellular mechanism by which circadian rhythms -- also known as the body clock -- modify energy metabolism and also have identified novel compounds that control this action. The findings point to potential treatments for disorders triggered by circadian rhythm dysfunction, ranging from insomnia and obesity to diabetes and cancer.

 

UC Irvine's Paolo Sassone-Corsi, one of the world's leading researchers on the genetics of circadian rhythms, led the studies and worked with international groups of scientists. Their results are detailed in two companion pieces appearing this week in the early online edition of the Proceedings of the National Academy of Sciences.

http://www.sciencedaily.com/releases/2013/01/130122162329.htm

 

Don’t Ignore the Snore: Snoring May Be Early Sign of Future Health Risks

Jan. 24, 2013 —
Science Daily/Henry Ford Health System

https://www.sciencedaily.com/images/2013/01/130124122741_1_540x360.jpg
Here's a wake-up call for snorers: Snoring may put you at a greater risk than those who are overweight, smoke or have high cholesterol to have thickening or abnormalities in the carotid artery, according to new research.
Credit: © Tracy King / Fotolia

Here's a wake-up call for snorers: Snoring may put you at a greater risk than those who are overweight, smoke or have high cholesterol to have thickening or abnormalities in the carotid artery, according to researchers at Henry Ford Hospital in Detroit.

The increased thickening in the lining of the two large blood vessels that supply the brain with oxygenated blood is a precursor to atherosclerosis, a hardening of the arteries responsible for many vascular diseases.

"Snoring is more than a bedtime annoyance and it shouldn't be ignored. Patients need to seek treatment in the same way they would if they had sleep apnea, high blood pressure or other risk factors for cardiovascular disease," says lead study author Robert Deeb, M.D., with the Department of Otolaryngology-Head & Neck Surgery at Henry Ford.

"Our study adds to the growing body of evidence suggesting that isolated snoring may not be as benign as first suspected. So instead of kicking your snoring bed partner out of the room or spending sleepless nights elbowing him or her, seek out medical treatment for the snorer."

The study reveals changes in the carotid artery with snorers -- even for those without sleep apnea -- likely due to the trauma and subsequent inflammation caused by the vibrations of snoring.

Study results will be presented January 25 at the 2013 Combined Sections Meeting of the Triological Society in Scottsdale, Ariz. It has been submitted to The Laryngoscope journal for publication.

Obstructive sleep apnea (OSA) -- a sleep disorder that occurs due to the collapse of the airway in the throat during sleep and causes loud snoring and periodic pauses in breathing -- has long been linked to cardiovascular disease, along with a host of other serious health issues.

But the risk for cardiovascular disease may actually begin with snoring, long before it becomes OSA. Until now, there was little evidence in humans to show a similar connection between snoring and cardiovascular risk.

For the Henry Ford study, Dr. Deeb and senior study author Kathleen Yaremchuk, M.D., reviewed data for 913 patients who had been evaluated by the institution's sleep center.

Patients, ages 18-50, who had participated in a diagnostic sleep study between December 2006 and January 2012 were included in the study. None of the participants had sleep apnea.

In all, 54 patients completed the snore outcomes survey regarding their snoring habits, as well as underwent a carotid artery duplex ultrasound to measure the intima-media thickness of the carotid arteries.

Carotid intima-media thickness, a measurement of the thickness of the innermost two layers of the arterial wall, may be used to detect the presence and to track the progression of atherosclerotic disease. Intima-media thickness is the first sign of carotid artery disease.

Compared to non-snorers, snorers were found to have a significantly greater intima-media thickness of the carotid arteries, the study finds.

The study also revealed no statistically significant differences in intima-media thickness for patients with or without some of the traditional risk factors for cardiovascular disease -- smoking, diabetes, hypertension or hypercholesterolemia.

"Snoring is generally regarded as a cosmetic issue by health insurance, requiring significant out-of-pocket expenses by patients. We're hoping to change that thinking so patients can get the early treatment they need, before more serious health issues arise."

The Henry Ford research team plans to conduct another long-term study on this topic, particularly to determine if there's an increased incidence of cardiovascular events in patients who snore.
http://www.sciencedaily.com/releases/2013/01/130124122741.htm

 

Dietary Nutrients Associated With Certain Sleep Patterns

Feb. 6, 2013 —
Science Daily/Perelman School of Medicine at the University of Pennsylvania

https://www.sciencedaily.com/images/2013/02/130206093542_1_540x360.jpg
A new study shows for the first time that certain nutrients may play an underlying role in short and long sleep duration and that people who report eating a large variety of foods -- an indicator of an overall healthy diet -- had the healthiest sleep patterns.
Credit: © WavebreakmediaMicro / Fotolia

"You are what you eat," the saying goes, but is what you eat playing a role in how much you sleep? Sleep, like nutrition and physical activity, is a critical determinant of health and well-being. With the increasing prevalence of obesity and its consequences, sleep researchers have begun to explore the factors that predispose individuals to weight gain and ultimately obesity. Now, a new study from the Perelman School of Medicine at the University of Pennsylvania shows for the first time that certain nutrients may play an underlying role in short and long sleep duration and that people who report eating a large variety of foods -- an indicator of an overall healthy diet -- had the healthiest sleep patterns.

The authors found that total caloric intake varied across groups. Short sleepers consumed the most calories, followed by normal sleepers, followed by very short sleepers, followed by long sleepers. Food variety was highest in normal sleepers, and lowest in very short sleepers. Differences across groups were found for many types of nutrients, including proteins, carbohydrates, vitamins and minerals.

"Overall, people who sleep 7 -- 8 hours each night differ in terms of their diet, compared to people who sleep less or more. We also found that short and long sleep are associated with lower food variety," said Dr. Grandner. "
http://www.sciencedaily.com/releases/2013/02/130206093542.htm

 

Permanent Stress Can Cause Type 2 Diabetes in Men

Feb. 7, 2013 —
Science Daily/University of Gothenburg
Men who reported permanent stress have a significantly higher risk of developing type 2 diabetes than men who reported no stress. This is the finding of a 35-year prospective follow-up study of 7,500 men in Gothenburg, by the University of Gothenburg, Sweden.

Since the 1970s, a large population based cohort study has been undertaken at the Sahlgrenska Academy, University of Gothenburg to monitor the health of men born in Gothenburg between 1915 and 1925.

Using this unique material, researchers are now able to show that permanent stress significantly increases the risk of type 2 diabetes.

Of the total sample, 6,828 men without any previous history of diabetes, coronary artery disease or stroke were analysed. A total of 899 of these men developed diabetes during the follow up.

Stress at baseline in this study was measured using a single item question in which they were asked to grade their stress level on a six-point scale, based on factors such as irritation, anxiety and difficulties in sleeping related to conditions at work or at home. At baseline, 15.5% of the men reported permanent stress related to conditions at work or home, either during the past one year or during the past five years.

The results show that men who have reported permanent stress had a 45 percent higher risk of developing diabetes, compared with men who reported to have no or periodic stress. The link between stress and diabetes has been statistically significant, even after adjusting for age, socioeconomic status, physical inactivity, BMI, systolic blood pressure and use of blood pressure-lowering medication.

"Today, stress is not recognized as a preventable cause of diabetes" says researcher Masuma Novak, who led the study. "As our study shows that there is an independent link between permanent stress and the risk of developing diabetes, which underlines the importance of preventive measure."
http://www.sciencedaily.com/releases/2013/02/130207114418.htm

 

Stress at Work Very Unlikely to Cause Cancer

Feb. 7, 2013

Science Daily/BMJ-British Medical Journal

Work-related stress is not linked to the development of colorectal, lung, breast or prostate cancers, a study suggests.

Around 90% of cancers are linked to environmental exposures and whilst some exposures are well recognised (such as UV radiation and tobacco smoke), others are not (psychological factors such as stress).

Stress can cause chronic inflammation which has been shown to have various roles in the development of cancer, plus stressed individuals are more likely to smoke, consume excessive amounts of alcohol and be obese -- all of which are cancer risk factors.

So far, only a few studies have examined the associations between work-related stress and cancer risk. These also had unclear conclusions.

Researchers from the IPD-Work Consortium, led by the Finnish Institute of Occupational Health and University College London therefore carried out a meta-analysis of 12 studies involving 116,000 participants aged 17 to 70, from Finland, France, the Netherlands, Sweden, Denmark, and the UK.

Psychological stress at work was assessed using a validated measure, job strain. Job strain was categorised into: high strain job (high demands and low control), active job (high demands and high control), passive job (low demands and low control) and low strain job (low demands and high control).

Data on cancer events were obtained from national cancer or death registries and hospitalisation registries.

Rates were adjusted for age, sex, socioeconomic position, BMI, smoking and alcohol intake. Those with a BMI under 15 or over 50 were excluded from the study.

Results showed that 5,765 out of 116,056 (5%) participants developed some form of cancer in the average 12 year follow-up. Researchers found no evidence of an association between job strain and overall cancer risk. They suggest that many of the previously reported associations may have been chance findings or influenced by possible unmeasured common causes of stress and cancer, for example shift work.

Researchers conclude that the meta-analysis provided "no evidence for an association between job strain and overall cancer risk" suggesting that work-related psychological stress is unlikely to be an important factor for cancer. And although reducing work stress would improve the well-being of the general population, it is unlikely to have a marked impact on cancer burden at population-level.

http://www.sciencedaily.com/releases/2013/02/130207192233.htm

Insomnia Is Linked to Increased Risk of Heart Failure

March 6, 2013

Science Daily/European Society of Cardiology (ESC)

People who suffer from insomnia appear to have an increased risk of developing heart failure, according to the largest study to investigate the link.

The study, which is published online today in the European Heart Journal, followed 54,279 people between the ages of 20-89 for an average of more than 11 years, and found that those who suffered from three symptoms of insomnia had a more than three-fold increased risk of developing heart failure compared to those with no insomnia symptoms.

Dr Lars Laugsand, a post-doctoral fellow in the Department of Public Health, Norwegian University of Science and Technology, Trondheim, Norway, said: "We related heart failure risk to three major insomnia symptoms including trouble falling asleep, problems staying asleep, and not waking up feeling refreshed in the morning. In our study, we found that persons suffering from insomnia have increased risk of having heart failure. Those reporting suffering from all three insomnia symptoms simultaneously were at considerably higher risk than those who had no symptoms or only one or two symptoms."

However, he stressed that although the study shows that insomnia is linked to an increased risk of heart failure, it does not show that it causes it. "We do not know whether heart failure is really caused by insomnia, but if it is, insomnia is a potentially treatable condition using strategies such as following simple recommendations concerning sleeping habits (often referred to as sleep hygiene), and several psychological and pharmacological therapies. Evaluation of sleep problems might provide additional information that could be used in prevention of heart failure."

He said further research would be required to establish whether or not insomnia caused the condition. "It is still unclear why insomnia is linked to higher heart failure risk. We have some indications that there might be a biological cause, and one possible explanation could be that insomnia activates stress responses in the body that might negatively affect heart function. However, further research is also needed to find the possible mechanisms for this association."

Dr Laugsand and his colleagues collected data from men and women enrolled in the Nord-Trondelag Health study (HUNT) between 1995 and 1997 and who were free from heart failure when they joined. Heart failure is a condition in which the heart is unable to pump enough blood around the body at the right pressure. It usually occurs because the heart muscle has become too weak or stiff to work properly. The researchers followed the study participants until 2008, by which time there had been a total of 1412 cases of heart failure.

When participants joined the study they were asked whether they had difficulty going to sleep and staying asleep, with the possible answers being "never," "occasionally," "often" and "almost every night." They were also asked how often they woke up in the morning not feeling refreshed (non-restorative sleep): "never, few times a year," "one to two times per month," "once a week," "more than once a week."

After adjusting for factors that could affect the results, such as age, sex, marital status, education, shift work, blood pressure, cholesterol, diabetes, body mass index, physical activity, smoking, alcohol, any previous heart attack, depression and anxiety, the researchers found that having difficulties going to sleep and staying asleep almost every night, and having non-restorative sleep more than once a week were associated with an increased risk of heart failure when compared with people who never or rarely suffered from these symptoms. There was a trend showing a link between the frequency of the symptoms and the increased risk, although most of these findings did not reach statistical significance.

When they looked at the number of symptoms, the researchers found a statistically significant three-fold (353%) increased risk of heart failure for people who had all three insomnia symptoms, compared to those with none, after adjusting for most confounding factors apart from depression and anxiety. When they adjusted their findings to include depression and anxiety, the risk was still significant, with a slightly more than four-fold risk (425%) of heart failure.

The authors write in their paper: "We found a moderate risk increase related to the individual insomnia symptoms. However, the risk among those with all the three insomnia symptoms simultaneously was particularly high even after adjustment for established cardiovascular risk factors and psychological distress. This finding may be interpreted as suggesting that compromising some aspects of sleep may be somehow compensated for, and the net effect on cardiovascular disease may be limited. For example, having difficulty falling asleep might be compensated for by a satisfactory depth and a good continuity of sleep. However, if the initiation of sleep is poor and combined with repeated awakenings and superficial sleep, there may not be any compensatory mechanisms."

http://www.sciencedaily.com/releases/2013/03/130305200310.htm

Anxiety, Depression Identify Heart Disease Patients at Increased Risk of Dying

Mar. 19, 2013

Science Daily/Journal of the American Heart Association

Heart disease patients who have anxiety have twice the risk of dying from any cause compared to those without anxiety, according to new research in the Journal of the American Heart Association.

Studies show that depression is about three times more common in heart attack patients. The American Heart Association recommends that heart patients be screened for depression and treated if necessary.

Anxiety and depression each influence risk of death in unique ways. Anxiety, for example, increases activity of the sympathetic (adrenaline-producing) nervous system that controls blood pressure. "People who worry a lot are more likely to have difficulty sleeping and to develop high blood pressure," Watkins said. The link between depression and mortality is more related to behavioral risk factors, she said. "Depression results in lack of adherence to medical advice and treatments, along with behaviors like smoking and being sedentary."

http://www.sciencedaily.com/releases/2013/03/130319202148.htm

Short and Poor Sleepers Have a Higher Risk of Cardiovascular Disease

Mar. 20, 2013

Science Daily/Wageningen University and Research Centre

People who sleep poorly or not long enough have a higher risk of developing cardiovascular disease. This does not apply to people who sleep less than 6 hours, but wake up feeling fit and rested. Researchers from Wageningen University and the National Institute for Public Health and the Environment (RIVM) studied the link between the duration and quality of sleep and the incidence of cardiovascular disease among a group of 20.000 people.

The research team concluded that people who sleep for less than 6 hours and who also sleep badly are doubly unfortunate. The research showed that this group has a 65% higher risk of cardiovascular disease compared with people who sleep soundly for seven to eight hours. Short sleepers who wake up feeling fit and rested have the same chance of suffering a heart attack or stroke as longer sleepers.

The findings imply that sleep can be added to the list of traditional positive lifestyle factors (healthy eating habits, not smoking, moderate alcohol consumption and sufficient physical activity). People who follow these 'lifestyle rules' have a 57% lower risk of developing cardiovascular disease, and their chance of dying from cardiovascular disease is 2/3 lower.

http://www.sciencedaily.com/releases/2013/03/130320115108.htm

Adult Health Habits Influence How Much We Shrink With Age

Apr. 1, 2013 —
Science Daily/University of Southern California
Even if you didn't eat your veggies or drink your milk as a child, your height is still in your hands, reveal new findings by economists from the University of Southern California, Harvard University and Peking University.

Using unique data from a new massive longitudinal survey of 17,708 adults beginning at age 45, the researchers show for the first time that lifestyle choices we make in adulthood -- and not just the hand we're dealt as children -- influence how tall we stand as we age.

"Had we only examined the correlations between measured height and health, we would have missed this important insight," said John Strauss, professor of economics at USC, and an investigator on a study published in the April 2013 issue of the American Economic Journal: Applied Economics. "The evidence shows that it is not only early-life events that are associated with how we age, but health decisions in later life as well."

While prior work has looked for the connection between height and health -- both in childhood and adulthood -- the researchers are the first to examine height loss as we age. They show that regardless of your maximum height, the loss of height over time is also an important indicator for other health issues as we age.

For example, the research reveals an especially strong relationship between height loss and cognitive health. Those who had lost more height were also much more likely to perform poorly on standard tests of cognitive health such as short-term memory, ability to perform basic arithmetic and awareness of the date.

Among the socioeconomic factors that correlate to height loss, urban dwellers had much less height loss than those in rural areas, the researchers found, in a country where there has been significant migration to urban areas in the last few decades. In addition, having completed primary school, rather than being illiterate, is associated with 0.9 cm less height shrinkage in men -- a large difference when considering that overall average height loss for men is 3.3 cm. Completing high school meant an additional 1 cm less in shrinkage.

For women, having completed primary school was the difference in 0.6 cm of shrinkage, compared to average overall height decrease of 3.8 cm.

"Height has been recognized as an acceptable proxy for childhood health conditions, but there are complications there," says USC economist Geert Ridder, a co-investigator on the study. "Some of adult health might be determined by childhood circumstances, but people shrink differentially, and that shrinkage is also a measure of adult health conditions."

All humans go through physical changes with age, including an increase in body fat and decrease in bone mass. But a decrease in height can be further exacerbated by certain kinds of arthritis, inflammation of spine joints or osteoporosis, which other studies have shown are associated with such lifestyle choices as diet, exercise and smoking.

The researchers used new data from the China Health and Retirement Longitudinal Study, a groundbreaking sampling project led by USC economist Strauss, Yaohui Zhao of the China Center for Economic Research (CCER) at Peking University and Gonghuan Yang of the Chinese Academy of Medical Sciences and Peking Union Medical College, that covers 150 counties randomly chosen throughout China.

The baseline for the survey was collected from June 2011 to March 2012 and includes both subjective self-reported responses to survey questions as well as objective physical measurements such as blood tests. These physical measurements and personal interviews will be followed-up with the same 17,708 people every two years -- capturing, for the first time, critical data about human aging in the most populous and most rapidly aging country in the world.

For example, recent changes in social security policy and health insurance in China provide a valuable opportunity for researchers to study how health care actually affects health and aging in a large population, with insights for other developing health care systems worldwide, as well as an opportunity to identify possible under-diagnosis of various chronic conditions.

The researchers will also be able to examine the role specific historical events in China may have had on long-term health, including whether there are health and aging differences among those who were "sent-down" during the Cultural Revolution.

The baseline CHARLS data is publicly available to researchers at http://charls.ccer.edu.cn. The research is supported by the National Institute of Aging, the China Natural Science Foundation, the Fogarty International Center of the National Institutes of Health and the World Bank.

To estimate full adult height for older study participants, the researchers examined relationships between current height and the length of limbs, which do not shrink with age, from younger survey participants who have not yet started shrinking.
http://www.sciencedaily.com/releases/2013/04/130401101017.htm

 

Decreased Melatonin Secretion: Risk of Developing Type 2 Diabetes

Apr. 2, 2013

Science Daily/American Medical Association (AMA)

With previous evidence suggesting that melatonin may have a role in glucose metabolism, researchers have found an independent association between decreased secretion of melatonin and an increased risk for the development of type 2 diabetes, according to a study in the April 3 issue of JAMA.

"Melatonin receptors have been found throughout the body in many tissues including pancreatic islet cells, reflecting the widespread effects of melatonin on physiological functions such as energy metabolism and the regulation of body weight," according to background information in the article. "Loss-of-function mutations in the melatonin receptor are associated with insulin resistance and type 2 diabetes. Additionally, in a cross-sectional analysis of persons without diabetes, lower nocturnal melatonin secretion was associated with increased insulin resistance." A prospective association between melatonin secretion and type 2 diabetes has not been previously reported.

Ciaran J. McMullan, M.D., of Brigham and Women's Hospital, Boston, and colleagues conducted a study to investigate the association of melatonin secretion and the incidence of type 2 diabetes. The analysis consisted of a case-control study nested within the Nurses' Health Study cohort. Among participants without diabetes who provided urine and blood samples at baseline in 2000, the researchers identified 370 women who developed type 2 diabetes from 2000-2012 and matched 370 controls. Statistical analyses for determining associations between melatonin secretion at baseline and incidence of type 2 diabetes included controlling for demographic characteristics, lifestyle habits, measures of sleep quality, and biomarkers of inflammation and endothelial dysfunction.

Secretion of melatonin varied widely among participants in the study; the median (midpoint) urinary ratio of 6-sulfatoxymelatonin to creatinine was 67.0 ng/mg in the highest category compared with 14.4 ng/mg in the lowest category. The median ratio was significantly higher among controls (36.3 ng/mg) than among cases (28.2 ng/mg). Insulin sensitivity was higher among women with higher urinary ratios of 6-sulfatoxymelatonin to creatinine.

The researchers found that after controlling for body mass index and other lifestyle factors, menopausal status, family history of diabetes, history of hypertension, use of beta-blockers or non-steroidal anti-inflammatory drugs, region of the United States, and plasma biomarkers of diabetes risk, participants in the lowest category of urinary ratio of 6-sulfatoxymelatonin to creatinine had a 2.2 times higher odds of developing type 2 diabetes compared to participants in the highest category.

Women in the lowest category of melatonin secretion had an estimated diabetes incidence rate that was more than double that of women in the highest category (as measured by cases per 1,000 person-years).

"It is interesting to postulate from these data, in combination with prior literature, whether there is a causal role for reduced melatonin secretion in diabetes risk. Further studies are needed to determine whether increasing melatonin levels (endogenously via prolonged nighttime dark exposure or exogenously via supplementation) can increase insulin sensitivity and decrease the incidence of type 2 diabetes," the authors conclude.

http://www.sciencedaily.com/releases/2013/04/130402162420.htm

 

Fetal Exposure to Excessive Stress Hormones Linked to Adult Mood Disorders

Apr. 6, 2013

Science Daily/British Neuroscience Association

Exposure of the developing fetus to excessive levels of stress hormones in the womb can cause mood disorders in later life and now, for the first time, researchers have found a mechanism that may underpin this process, according to research presented April 7 at the British Neuroscience Association Festival of Neuroscience (BNA2013) in London.

Adverse environments experienced while in the womb, such as in cases of stress, bereavement or abuse, will increase levels of glucocorticoids in the mother, which may harm the growing baby. Glucocorticoids are naturally produced hormones and they are also known as stress hormones because of their role in the stress response.

"The stress hormone cortisol may be a key factor in programming the fetus, baby or child to be at risk of disease in later life. Cortisol causes reduced growth and modifies the timing of tissue development as well as having long lasting effects on gene expression," she will say.

Puberty is another sensitive time of development and stress experienced at this time can also be involved in programming adult mood disorders. Prof Holmes and her colleagues have found evidence from imaging studies in rats that stress in early teenage years could affect mood and emotional behaviour via changes in the brain's neural networks associated with emotional processing.

Prof Holmes will say: "We showed that in stressed 'teenage' rats, the part of the brain region involved in emotion and fear (known as amygdala) was activated in an exaggerated fashion when compared to controls. The results from this study clearly showed that altered emotional processing occurs in the amygdala in response to stress during this crucial period of development."

http://www.sciencedaily.com/releases/2013/04/130407090835.htm

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