Sleep / Sleep Disorders / Insomnia Cholesterol Genetics Cardiovascular / Cardiology Sleep deprivation may lower 'good' cholesterol

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Previous studies have suggested that lack of sleep may increase the risk for cardiovascular disease, and a new study may help explain why; researchers found that sleep deprivation may have a negative impact on cholesterol levels.

Lack of sleep may have a big impact on cholesterol, a new study suggests.

Published in the journal Scientific Reports, the study found that sleep loss leads to changes in genes that are responsible for regulating cholesterol levels.
What is more, two population cohorts reveal that people who experience sleep deprivation may have fewer high-density lipoproteins (HDL) - known as the "good" cholesterol - than those who have sufficient sleep.
HDL cholesterol is responsible for removing low-density lipoproteins (LDL) - the "bad" cholesterol - from the arteries.
LDL cholesterol contributes to atherosclerosis - a build-up of plaque in the arteries that can increase the risk for heart attack and stroke - so a robust HDL cholesterol level is important for protecting heart health.
The team reached its findings by conducting experimental and epidemiological analyses.
For the experimental analysis, the researchers enrolled 21 participants who were required to sleep in a laboratory-controlled condition for 5 nights
The sleep duration for 14 of these participants was restricted to just 4 hours a night, while the remaining seven participants enjoyed sufficient sleep each night.

Lack of sleep reduced activity in lipoprotein-regulating genes

Blood samples were taken from all subjects during the study period, which the team analyzed for gene expression and lipoprotein levels.
Compared with participants who had sufficient sleep, the researchers found that those who experienced sleep loss had reduced expression for genes that encode for lipoproteins - that is, there was reduced activity in genes that are responsible for regulating cholesterol levels.
For the epidemiological analysis, the researchers assessed the data of 2,739 participants from one of two Finnish population studies: Dietary, Lifestyle and Genetic determinants of Obesity and Metabolic syndrome (DILGOM) study, and the Cardiovascular Risk in Young Finns Study (YFS).
In the DILGOM study, participants completed questionnaires in which they were asked whether they got enough sleep each night. Subjects who answered "seldom" or "never" were deemed as having "subjective sleep insufficiency."
In the YFS study, subjects were asked how many hours they slept each night and how many hours they need each night to fell well-rested. Their subjective sleep duration was then subtracted from their subjective sleep need in order to determine which participants could be deemed as having sleep deprivation.

Lower circulating HDL with sleep deprivation in population cohorts

On analyzing the blood samples of the participants, once again, the researchers found that subjects who were not getting sufficient sleep had reduced expression of lipoprotein-encoding genes, compared with those who were getting enough sleep.
Additionally, subjects who were experiencing lack of sleep had lower levels of circulating HDL.
The team says the findings from both analyses suggest that just a short period of sleep deprivation may have a big impact on health, and they may explain why people who fail to get enough sleep may be at greater risk for cardiovascular disease.
Study co-author Vilma Aho, from the University of Helsinki Sleep Team, says:

"The experimental study proved that just 1 week of insufficient sleep begins to change the body's immune response and metabolism. Our next goal is to determine how minor the sleep deficiency can be while still causing such changes."

US suicide rate surges, particularly among white people

Public health officials are alarmed by the steep rise in suicides

The suicide rate in the US has surged to its highest level in almost three decades, according to a new report.

The increase is particularly pronounced among middle-age white people who now account for a third of all US suicides.
The Centers for Disease Control and Prevention (CDC) report did not offer an explanation for the steep rise.
However, other experts have pointed to increased abuse of prescription opiates and the financial downturn that began in 2008 as likely factors.
The report did not break down the suicides by education level or income, but previous studies found rising suicide rates among white people without university degrees.
"This is part of the larger emerging pattern of evidence of the links between poverty, hopelessness and health," Robert D Putnam, a professor of public policy at Harvard, told the New York Times.
CDC reported on Friday that suicides have increased in the US to a rate of 13 per 100,000 people, the highest since 1986.
Meanwhile, homicides and deaths from ailments like cancer and heart disease have declined.
In the past, suicides have been most common among white people, but the recent increases have been sharp.

Image copyright CDC

The overall suicide rate rose by 24% from 1999 to 2014, according to the CDC. However, the rate increased 43% among white men ages 45 to 64 and 63% for women in the same age-range.
In 2014, more than 14,000 middle-aged white people killed themselves.
That figure is double the combined suicides total for all blacks, Hispanics, Asians, Pacific Islanders, American Indians, and Alaska Natives.
The suicide rate declined for only two groups: black men and all people over 75.

Final piece of type 1 diabetes puzzle solved

A complete picture of the areas that the immune system attacks to cause type 1 diabetes has finally been revealed by scientists.

The study, discovered the fifth and final critical target at which the immune system errantly takes aim.
The team at the University of Lincoln say the findings could help develop new ways to prevent and treat the disease.
Diabetes UK said the findings were "impressive".
In type 1 diabetes, the immune system destroys the beta cells that make insulin - the hormone needed to keep blood sugar levels under control.
Studies looking at the unique antibodies made by patients with type 1 showed there were five key targets that the immune system attacked.
But working out exactly what they were has been like identifying someone from their silhouette.
Studies long ago discovered some of the targets, but the final one has proved elusive for two decades.
Dr Michael Christie, who led the research at the University of Lincoln, told the BBC: "With this new discovery, we have now finished identifying what the immune system is targeting - we have the complete picture."
The targets are:

• Insulin
• Glutamate decarboxylase
• IA-2
• Zinc transporter-8
• And the final piece of the puzzle, tetraspanin-7

The more technically named ones are largely involved in secreting or storing the hormone insulin.
Knowledge of some of these targets is already being used in a trial at King's College London that is aiming to stall the progression of type
But Dr Christie says having the complete picture could help transform care for type 1 patients.
He said: "Once the immune system decides it wants to get rid of something it's very hard to stop, so diabetes has proved to be a difficult disease to prevent.
"So we're hoping that, by having identified the major targets in the disease, we can find ways to prevent it by blocking the immune response to these five proteins without leaving that person vulnerable to infections.
"With recent improvements in our understanding of the disease I'm very hopeful we'll develop a treatment now; I have a lot more confidence than even five years ago."

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Diabetes

There are two main types of diabetes -

• Type 1 - where the pancreas does not produce any insulin
• Type 2 - where the pancreas does not produce enough insulin - or the body's cells do not react to insulin

Type 1 diabetes can develop at any age, but usually appears before the age of 40, particularly in childhood.
Around 10% of all diabetes is type 1, but it is the most common type of childhood diabetes, so it is sometimes called juvenile diabetes or early-onset diabetes
Type 2 diabetes is largely caused by poor lifestyle. Around 90% of adults with diabetes have type 2, and it tends to develop later in life than type 1.
Source: NHS Choices