Tag: sleep disruption

Categories : Ageing NeurologyTags : Leave a comment

Poor Sleep May Accelerate Brain Ageing

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Poor sleep may accelerate brain ageing, a new study shows. Photo by Andrea Piacquadio

People who sleep poorly are more likely than others to have brains that appear older than they actually are. This is according to a comprehensive brain imaging study from Karolinska Institutet, published in the journal eBioMedicine. Increased inflammation in the body may partly explain the association.

Poor sleep has been linked to dementia, but it is unclear whether unhealthy sleep habits contribute to the development of dementia or whether they are rather early symptoms of the disease. In a new study, researchers at Karolinska Institutet have investigated the link between sleep characteristics and how old the brain appears in relation to its chronological age. 

The study includes 27 500 middle-aged and older people from the UK Biobank who underwent magnetic resonance imaging (MRI) of the brain. Using machine learning, the researchers estimated the biological age of the brain based on over a thousand brain MRI phenotypes. 

Low-grade inflammation 

The participants’ sleep quality was scored based on five self-reported factors: chronotype (being a morning/evening person), sleep duration, insomnia, snoring, and daytime sleepiness. They were then divided into three groups: healthy (≥ 4 points), intermediate (2-3 points), or poor (≤ 1 point) sleep. 

“The gap between brain age and chronological age widened by about six months for every 1-point decrease in healthy sleep score,” explains Abigail Dove, researcher at the Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, who led the study. “People with poor sleep had brains that appeared on average one year older than their actual age.” 

To understand how poor sleep can affect the brain, the researchers also examined levels of low-grade inflammation in the body. They found that inflammation could explain just over ten per cent of the link between poor sleep and older brain age. 

“Our findings provide evidence that poor sleep may contribute to accelerated brain ageing and point to inflammation as one of the underlying mechanisms,” says Abigail Dove. “Since sleep is modifiable, it may be possible to prevent accelerated brain ageing and perhaps even cognitive decline through healthier sleep.” 

Several possible explanations 

Other possible mechanisms that could explain the association are negative effects on the brain’s waste clearance system, which is active mainly during sleep, or that poor sleep affects cardiovascular health, which in turn can have a negative impact on the brain. 

Participants in the UK Biobank are healthier than the general UK population, which could limit the generalisability of the findings. Another limitation of the study is that the results are based on self-reported sleep. 

The study was conducted in collaboration with researchers from the Swedish School of Sport and Health Sciences, and Tianjin Medical University and Sichuan University in China, among others. It was funded by the Alzheimer’s Foundation, the Dementia Foundation, the Swedish Research Council, the Loo and Hans Osterman Foundation for Medical Research, and the Knowledge Foundation. The researchers report no conflicts of interest. 

Source: Karolinska Institutet

Categories : PaediatricsTags :

How Much Infants Cry is Mostly Down to Genetics

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Photo by William Fortunato

How much an infant cries is largely steered by their genetics and there is probably not much that parents can do about it. This has been shown in a new Swedish twin study from Uppsala University and Karolinska Institutet in which researchers investigated how genetics and environment influence infants’ crying duration, sleep quality and ability to settle during the first months of life.

The study, which was recently published in JCPP Advances, is based on questionnaire responses from parents of 1000 twins spread across Sweden. The parents were asked questions about their children’s sleep, crying and ability to settle when the twins were two months old and then again at five months old. The researchers were interested in finding out how genetics and environment influence these behaviours during the first months of life – something that no study has done before.

The clearest results were seen when the researchers analysed how long the children cried per day.

“What we found was that crying is largely genetically determined. At the age of two months, the children’s genetics explain about 50 per cent of how much they cry. At five months of age, genetics explain up to 70% of the variation. For parents, it may be a comfort to know that their child’s crying is largely explained by genetics, and that they themselves have limited options to influence how much their child cries,” says Charlotte Viktorsson, postdoctoral fellow in psychology and lead author of the study.

The parents who participated in the study were asked how long their children cried, how often they woke up at night, and how long it took until they settled. There was large individual variation between the children. For example, some children could wake up a total of up to 10 times per night. The figures below show averages.

2 months:
Crying duration (per 24 hours): about 72 minutes
Wakeups: 2.2 times per night
Time until settled: about 20 minutes

5 months:
Crying duration (per 24 hours): about 47 minutes
Wakeups: 2.1 times per night
Time until settled: about 14 minutes

The remaining percentage that cannot be explained by genetics was explained by what the researchers call ‘unique environment’ – factors in the children’s environment or life situation that are unique to each child and cannot be identified precisely from the questionnaire responses.

Charlotte Viktorsson is the lead author of the study that investigated how genetics and environment influence infants’ crying, sleep, and ability to settle during the first months of life. Photo: Mikael Wallerstedt

Twin studies reveal the importance of genetics

The participants were recruited by letter, which was sent to families with twins aged 1–2 months. These families were identified from the population register. To be able to capture how much of a behaviour is genetically determined, the researchers compared identical (monozygotic) twins with fraternal (dizygotic) twins. The advantage of studying twins is that they share important factors such as home environment, family situation, and socio-economic status. If identical twins become more similar to each other than fraternal twins in terms of a certain trait, such as how much they cry, it is seen as an expression of the importance of genetics for that trait.

The environment plays a role in infants’ time until settled

Using the same method, the researchers also analysed the number of times the children woke up at night. Here, genetics played less of a role. The number of awakenings during the night was mainly influenced by environmental factors, which can include sleep routines and the environment in which the child sleeps

In the questionnaire, the parents were also asked to state how long it took from the child being put to bed until they were asleep.

“How rapidly the infant settles was primarily due to the environment at 2 months of age, but by 5 months, their genetics had gained some significance. This reflects the rapid development that occurs in infants, and may indicate that parents’ efforts in getting their child to settle may have the greatest impact in the first months,” says Charlotte Viktorsson, who led the study.

However, it is difficult to draw conclusions about which interventions are effective based on this type of observational study.

“Although we cannot see which specific environmental factors influence the number of awakenings during the night, or how long it takes until the child settles, this study points out a direction for future studies with a focus on sleep routines,” she says.

The researchers have followed the twins up to 36 months of age, allowing them to see how sleep and crying change as the children get older. The current study is thus the first in order based on this data.

Source: Uppsala University

Categories : Mental HealthTags :

Why Frequent Nightmares May Shorten Your Life by Years

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Photo by Kahfiara Krisna on Unsplash

Timothy Hearn, Anglia Ruskin University

Waking up from a nightmare can leave your heart pounding, but the effects may reach far beyond a restless night. Adults who suffer bad dreams every week were almost three times more likely to die before age 75 than people who rarely have them.

This alarming conclusion – which is yet to be peer reviewed – comes from researchers who combined data from four large long-term studies in the US, following more than 4,000 people between the ages of 26 and 74. At the beginning, participants reported how often nightmares disrupted their sleep. Over the next 18 years, the researchers kept track of how many participants died prematurely – 227 in total.

Even after considering common risk factors like age, sex, mental health, smoking and weight, people who had nightmares every week were still found to be nearly three times more likely to die prematurely – about the same risk as heavy smoking.

The team also examined “epigenetic clocks” – chemical marks on DNA that act as biological mileage counters. People haunted by frequent nightmares were biologically older than their birth certificates suggested, across all three clocks used (DunedinPACE, GrimAge and PhenoAge).

The science behind the silent scream

Faster ageing accounted for about 39% of the link between nightmares and early death, implying that whatever is driving the bad dreams is simultaneously driving the body’s cells towards the finish line.

How might a scream you never utter leave a mark on your genome? Nightmares happen during so-called rapid-eye-movement sleep when the brain is highly active but muscles are paralysed. The sudden surge of adrenaline, cortisol and other fight-or-flight chemicals can be as strong as anything experienced while awake. If that alarm bell rings night after night, the stress response may stay partially switched on throughout the day.

Photo by Andrea Piacquadio

Continuous stress takes its toll on the body. It triggers inflammation, raises blood pressure and speeds up the ageing process by wearing down the protective tips of our chromosomes.

On top of that, being jolted awake by nightmares disrupts deep sleep, the crucial time when the body repairs itself and clears out waste at the cellular level. Together, these two effects – constant stress and poor sleep – may be the main reasons the body seems to age faster.

The idea that disturbing dreams foreshadow poor health is not entirely new. Earlier studies have shown that adults tormented by weekly nightmares are more likely to develop dementia and Parkinson’s disease, years before any daytime symptoms appear.

Growing evidence suggests that the brain areas involved in dreaming are also those affected by brain diseases, so frequent nightmares might be an early warning sign of neurological problems.

Nightmares are also surprisingly common. Roughly 5% of adults report at least one each week and another 12.5% experience them monthly.

Because they are both frequent and treatable, the new findings elevate bad dreams from a spooky nuisance to a potential public health target. Cognitive behavioural therapy for insomnia, imagery-rehearsal therapy – where sufferers rewrite the ending of a recurrent nightmare while awake – and simple steps such as keeping bedrooms cool, dark and screen free have all been shown to curb nightmare frequency.

Before jumping to conclusions, there are a few important things to keep in mind. The study used people’s own reports of their dreams, which can make it hard to tell the difference between a typical bad dream and a true nightmare. Also, most of the people in the study were white Americans, so the findings might not apply to everyone.

And biological age was measured only once, so we cannot yet say whether treating nightmares slows the clock. Crucially, the work was presented as a conference abstract and has not yet navigated the gauntlet of peer review.

Despite these limitations, the study has important strengths that make it worth taking seriously. The researchers used multiple groups of participants, followed them for many years and relied on official death records rather than self-reported data. This means we can’t simply dismiss the findings as a statistical fluke.

If other research teams can replicate these results, doctors might start asking patients about their nightmares during routine check-ups – alongside taking blood pressure and checking cholesterol levels.

Therapies that tame frightening dreams are inexpensive, non-invasive and already available. Scaling them could offer a rare chance to add years to life while improving the quality of the hours we spend asleep.

Timothy Hearn, Senior Lecturer in Bioinformatics, Anglia Ruskin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Categories : Mental HealthTags :

Job Strain Compromises Sleep Quality Years Later

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Photo by Andrea Piacquadio

In a recent study published in the American Journal of Industrial Medicine, middle aged workers in the US who reported high job strain at the start of the study experienced significantly more sleep disturbances over an average follow-up of nine years.

The study analysed data from 1721 workers, with an average age of 51 years, who participated in the Midlife in the United States (MIDUS) study. Sleep disturbances were assessed with an established scale, based on four sleep-related symptoms: trouble falling asleep, waking up during the night and having difficulty going back to sleep, waking up too early in the morning and being unable to get back to sleep, and feeling unrested during the day no matter how many hours of sleep.

The team used six different formulations to quantify job strain based on Karasek’s Job‐Demand‐Control model, which defines job strain as a combination of high job demand and low job control. All formulations showed significant associations between higher job strain at baseline and increased sleep disturbances over time.

“Our findings also suggest that the continuous formulations of job strain demonstrate better model performance with consistent and robust results, offering empirical evidence for future psychosocial occupational health research in the United States,” said the first author Yijia Sun, an MS candidate at the University of California, Los Angeles.

Corresponding author Jian Li, MD, PhD, a professor of Work and Health at the University of California, Los Angeles, noted that there is an urgent need for workplace interventions to reduce stress. “Strategies such as redesigning workloads and promoting worker autonomy could play an important role in improving sleep health and workers’ well-being,” he said.

Source: Wiley

Categories : Diseases, Syndromes and Conditions Mental HealthTags :

Dengue Linked to Heightened Short- and Long-term Risk of Depression in Taiwan

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New study also uncovers short-term links with sleep disorders

Photo by Ekamelev on Unsplash

Analysis of the medical records of nearly 50 000 people who experienced dengue fever in Taiwan suggests that this disease is associated with elevated short- and long-term risk of depression. Hsin-I Shih and colleagues of National Cheng Kung University and National Health Research Institutes, Taiwan present these findings in the open-access journal PLOS Neglected Tropical Diseases.

People may develop dengue fever after being bitten by a mosquito carrying the dengue virus. Dengue fever can be mild, but it can also progress to life-threatening severity, and some people may have long-term health effects. Prior research has uncovered links between active dengue fever and psychiatric disorders, such as depression and anxiety. However, few studies have examined the long-term risk of such disorders after a dengue infection.

To address this knowledge gap, Shih and colleagues analysed the medical records of 45 334 dengue patients in Taiwan and, for comparison, 226 670 patients who did not experience dengue. Covering the years 2002 to 2015, the researchers examined whether dengue patients were more likely to develop anxiety, depressive disorders, and sleep disorders at various time points after infection. To help account for other factors that could influence mental health, the dengue patients were grouped with demographically similar non-dengue patients for statistical analysis.

The researchers found that the dengue patients had a greater likelihood of developing a depressive order across all timeframes, including less than three months, three to 12 months, and more than 12 months after their infection. Sleep disorders were only elevated within three to 12 months post-infection, and there was no observable elevated risk of anxiety.

Taking a closer look at patients whose dengue was severe enough for them to be hospitalized, the researchers found an elevated risk of anxiety disorders within the first three months of infection, as well as elevated risk of sleep disorders in the first 12 months. This subgroup also had elevated risk of depression across timeframes.

These findings suggest a potential link between dengue fever and subsequent depressive disorder. However, further research is needed to determine whether dengue contributes directly to development of depression, or if the association is due to some indirect mechanism.

The authors add: “This study highlights a significant association between dengue fever and an elevated risk of depression in both the short and long term, underscoring the need for further research into the mental health impacts of dengue infection.”

Provided by PLOS

Categories : NeurologyTags :

Poor Sleep Quality in Midlife Linked to Cognitive Problems Later on

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Photo by Andrea Piacquadio

People who have more disrupted sleep in their 30s and 40s may be more likely to have memory and thinking problems a decade later, according to new research published in Neurology. The study does not however prove that sleep quality causes cognitive decline, it only shows an association.

“Given that signs of Alzheimer’s disease start to accumulate in the brain several decades before symptoms begin, understanding the connection between sleep and cognition earlier in life is critical for understanding the role of sleep problems as a risk factor for the disease,” said study author Yue Leng, PhD, of the University of California, San Francisco.

“Our findings indicate that the quality rather than the quantity of sleep matters most for cognitive health in middle age.”

The study involved 526 people, average age of 40, who were followed for 11 years. Researchers looked at participants’ sleep duration and quality, and had them perform cognitive tests.

Participants wore a wrist activity monitor for three consecutive days on two occasions approximately one year apart to calculate their averages. Participants slept for an average of six hours.

Participants also reported bedtimes and wake times in a sleep diary and completed a sleep quality survey with scores ranging from zero to 21, with higher scores indicating poorer sleep quality. A total of 239 people, or 46%, reported poor sleep with a score greater than five. Participants also completed a series of memory and thinking tests.

Researchers also looked at sleep fragmentation, which measures repetitive short interruptions of sleep. They looked at both the percentage of time spent moving and the percentage of time spent not moving for one minute or less during sleep. Added together, participants had an average sleep fragmentation of 19%.

Researchers then divided participants into three groups based on their sleep fragmentation score. Of the 175 people with the most disrupted sleep, 44 had poor cognitive performance 10 years later, compared to 10 of the 176 people with the least disrupted sleep.

After adjusting for age, gender, race, and education, people who had the most disrupted sleep had more than twice the odds of having poor cognitive performance when compared to those with the least disrupted sleep.

There was no difference in cognitive performance at midlife for those in the middle group compared to the group with the least disrupted sleep.

“More research is needed to assess the link between sleep disturbances and cognition at different stages of life and to identify if critical life periods exist when sleep is more strongly associated with cognition,” Leng said.

“Future studies could open up new opportunities for the prevention of Alzheimer’s disease later in life.”

The amount of time people slept and their own reports of the quality of their sleep were not associated with cognition in middle age.

Source: American Academy of Neurology