Tag: heart disease

Google Street View predicts heart disease risk based on neighborhood features

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Researchers have used Google Street View to study hundreds of elements of the built environment, including buildings, green spaces, pavements and roads, and how these elements relate to each other and influence coronary artery disease in people living in these neighborhoods.

Their findings, published in the European Heart Journal today (Thursday), show that these factors can predict 63% of the variation in the risk of coronary heart disease from one area to another.

Coronary heart disease, where a build-up of fatty substances in the coronary arteries interrupts the blood supply to the heart, is one of the most common forms of cardiovascular disease.

Researchers say that using Google Street View can help provide an overview of physical environmental risk factors in the built and natural environments that could help not only in understanding risk factors in these environments, but ultimately help towards building or adapting towns and cities to make them healthier places to live.

The study was led by Prof. Sadeer Al-Kindi and Prof. Sanjay Rajagopalan from University Hospitals Harrington Heart & Vascular Institute and Case Western Reserve University, Ohio, USA, and Dr. Zhuo Chen, a post-doctoral fellow in Prof. Rajagopalan’s laboratory.

Prof. Rajagopalan said: “We have always been interested in how the environment, both the built and natural environment, influences cardiovascular disease. Here in America, they say that the zip code is a better predictor of heart disease than even personal measures of health. However, to investigate how the environment influences large populations in multiple cities is no mean task. Hence, we used machine vision-based approaches to assess the links between the built environment and coronary heart disease prevalence in US cities.”

The study included more than half a million Google Street View images of Detroit, Michigan; Kansas City, Missouri; Cleveland, Ohio; Brownsville, Texas; Fremont, California; Bellevue, Washington State; and Denver, Colorado. Researchers also collected data on rates of coronary heart disease according to ‘census tracts’. These are areas smaller than a US zip code that are home to an average of 4,000 people. The researchers used an approach called a convolutional neural network; a type of artificial intelligence that can recognize and analyze patterns in images to make predictions.

The research revealed that features of the built environment visible on Google Street View images could predict 63% of the variation in coronary heart disease between these small regions of US cities.

Prof. Al-Kindi added: “We also used an approach called attention mapping, which highlights some of the important regions in the image, to provide a semi-qualitative interpretation of some of the thousands of features that may be important in coronary heart disease. For instance, features like green space and walkable roads were associated with lower risk, while other features, such as poorly paved roads, were associated with higher risk. However, these findings need further investigation.

“We’ve shown that we can use computer vision approaches to help identify environmental factors influencing cardiovascular risk and this could play a role in guiding heart-healthy urban planning. The fact that we can do this at scale is something that is absolutely unique and important for urban planning.”

“With upcoming challenges including climate change and a shifting demographic, where close to 70% of the world’s population will live in urban environments, there is a compelling need to understand urban environments at scale, using computer vision approaches that can provide exquisite detail at an unparalleled level,” said Prof. Rajagopalan.

In an accompanying editorial, Dr. Rohan Khera from Yale University School of Medicine, USA said: “The association of residential location with outcomes often supersedes that of known biological risk factors. This is often summarised with the expression that a person’s postal code is a bigger determinant of their health than their genetic code. However, our ability to appropriately classify environmental risk factors has relied on population surveys that track wealth, pollution, and community resources.

“The study by Chen and colleagues presents a novel and more comprehensive evaluation of the built environment. This work creatively leverages Google’s panoramic street-view imagery that supplements its widely used map application.

“… an AI-enhanced approach to studying the physical environment and its association with cardiovascular health highlights that across our communities, measures of cardiovascular health are strongly encoded in merely the visual appearance of our neighborhoods. It is critical to use this information wisely, both in defining strategic priorities for identifying vulnerable communities and in redoubling efforts to improve cardiovascular health in communities that need it most.”

https://www.msn.com/en-gb/health/other/google-street-view-predicts-heart-disease-risk-based-on-neighborhood-features/ar-BB1kFeqv

Loneliness is linked to increased risk of death in patients with heart disease.

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By Steven Reinberg

Loneliness can take a heavy toll on heart patients — including a higher risk of death in the year after hospitalization, researchers found.

“This study confirms what has also been indicated in previous research regarding the serious health consequences of loneliness,” said lead researcher Anne Vinggaard Christensen, of Copenhagen University Hospital in Denmark.

“Loneliness should be considered a serious risk factor in patients with cardiac disease and should be included in risk evaluation of patients,” added Christensen, who is with the hospital’s heart center.

The Danish researchers cautioned, however, that their findings can’t prove that loneliness caused people to die, only that loneliness and the risk of death appear to be connected. But the differences in mortality between those who felt lonely and those who didn’t can’t be explained by their medical condition alone, they said.

Loneliness is a subjective experience, one that is distressing and unpleasant, the researchers noted.

The connection between loneliness and health is complex, Christensen said.

People who are lonely or socially isolated tend to have more unhealthy lifestyles. They smoke more, are less likely to be physically active and don’t take their medication, she said.

“Having a social network helps motivate people to make healthier choices,” Christensen said. “A social network can act as a buffer for stress.”

Also, lonely people have been found to have higher levels of stress hormones and lower immune function, she added.

“These different pathways are interconnected and help us understand why people feeling lonely or socially isolated experience worse health,” Christensen said.

James Maddux is a professor emeritus in the department of psychology at George Mason University in Fairfax, Va. Reviewing the findings, he took issue with the study’s methodology.

“My major concern about the methodology is that their measure of loneliness is rather weak and is not consistent with most studies about loneliness that I am familiar with,” Maddux said. He explained that the question used to measure loneliness failed to capture loneliness “as a profound sense of isolation and disconnected from others, accompanied by sadness and a longing to be with others. In other words, loneliness is painful.”

Still, even in its flawed state, the new study “adds to the growing research on the perils of social isolation among people in general and among older adults over 60 in particular,” said Maddux. “These results help reaffirm what we’ve learned so far about how unhealthy social isolation can be.”

For the study, Christensen and her colleagues collected data on more than 13,400 heart patients after they left the hospital from 2013 to 2014. Their average age was in the mid-60s.

Participants completed questionnaires on their health, psychological well-being, quality of life and levels of anxiety and depression.

Compared to people who didn’t feel lonely, those who said they were lonely were nearly three times more likely to be anxious and depressed and have a lower quality of life, the researchers found.

A year later, Christensen’s team found that feeling lonely had a significant impact on participants’ health.

Regardless of other factors, lonely women were nearly three times more likely to die than women who weren’t lonely, and lonely men were more than twice as likely to die, the researchers found.

Living alone, however, is not necessarily equal to feeling lonely, and it was linked to a lower risk of depression and anxiety than living with others.

But among men, living alone was tied with a 39% greater risk for poor heart health. This may be because men tend not to have an extensive support network after divorce or death of a spouse, compared with women, the researchers noted.

“Loneliness can have many causes and can occur even if you have people around you,” Christensen said.

For some, it would help to have a family member who remembers to ask how they are doing and is ready to listen, she said.

“For others, help with practical things might be what they need, and for some, the opportunity to talk to other patients who have gone through the same thing is helpful,” Christensen said.

She also stressed that the effects of loneliness are not confined to heart disease. “It’s also [detrimental] for individuals who do not suffer from an illness. Loneliness seems to be damaging to your health no matter what,” Christensen said.

The report was published online Nov. 4 in the journal Heart.

https://consumer.healthday.com/cardiovascular-health-information-20/misc-stroke-related-heart-news-360/risks-mount-for-lonely-hearts-after-cardiac-surgery-751879.html

Men Who Can Do More Than 40 Push-Ups Far Less Likely To Develop Heart Disease

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Here’s one way to predict your heart health: get down and give me 41. A new study finds that men who can perform at least 40 push-ups in one attempt are much less likely to suffer from heart disease within the next 10 years.

Researchers from the Harvard T.H. Chan School of Public health say their report is the first to show how push-up capacity is linked to heart disease. They found that middle-aged men who can log more than 40 push-ups in a single try have a 96% reduced risk of developing the potentially deadly condition and other related ailments, such as heart failure, compared to those who can complete no more than 10 push-ups.

For their study, the authors reviewed health data from 1,104 active male firefighters taken annually from 2000 to 2010. At the start of the study, the average participant was about 40 years old with an average body mass index of 28.7. The firefighters were tasked with performing as many push-ups as they could, and their treadmill tolerance was also tested.

By the end of the study period, 37 participants suffered from a heart disease-related condition — and 36 of those men weren’t able to log more than 40 push-ups in the initial test. The results of the treadmill test were not as clearly linked to heart disease diagnoses.

“Our findings provide evidence that push-up capacity could be an easy, no-cost method to help assess cardiovascular disease risk in almost any setting,” says the study’s first author, Justin Yang, an occupational medicine resident at the school. Surprisingly, push-up capacity was more strongly associated with cardiovascular disease risk than the results of submaximal treadmill tests.”

The authors note that because the study was completed by middle-aged men with active occupations, the results shouldn’t be considered the same for women or men who are less active or of different ages.

This study was published in JAMA Network Open.

Coffee drinkers may live longer

On By A.P.In coffee, HealthLeave a comment

Coffee lovers may live longer than those who don’t imbibe — with lower risks of early death from heart disease and neurological conditions such as Parkinson’s disease, a large U.S. study finds.

Researchers said the study, published online Nov. 16 in Circulation, adds to a large body of evidence on the good side of coffee.

People often think of coffee-drinking as a bad habit that they need to break, said study leader Dr. Frank Hu, a professor of nutrition and epidemiology at Harvard School of Public Health in Boston.

But, Hu said, many studies have linked moderate coffee intake to lower risks of developing various diseases — from heart disease and diabetes, to liver cancer, to neurological diseases such as Parkinson’s, multiple sclerosis and Alzheimer’s.

His team’s study, funded by the U.S. National Institutes of Health, adds another layer of evidence. It found that coffee drinkers were not only less likely to develop certain diseases — they also tended to live longer.

Over 30 years, nonsmokers who drank three to five cups of coffee a day were 15 percent less likely to die of any cause, versus nondrinkers. Specifically, they had lower rates of death from heart disease, stroke, neurological conditions and suicide.

Both regular coffee and decaf were linked to longer survival, the study found.

None of that proves coffee, itself, extends people’s lives or directly protects against certain diseases, Hu said. Other factors might explain the connection.

But, Hu added, his team did account for many of those factors. And the coffee benefit remained.

The findings are based on more than 200,000 U.S. doctors, nurses and other health professionals who were surveyed repeatedly over almost three decades. During that time, almost 32,000 study participants died.

It turned out that people who drank one to five cups of coffee at the outset had lower odds of dying during the study period when other lifestyle habits and certain health problems, such as high blood pressure and diabetes, were taken into account.

The relationship grew stronger when the researchers looked only at nonsmokers: Those who drank three to five cups of coffee a day were 15 percent less likely to die during the study period, compared with adults who didn’t drink coffee. Lower risks were even seen among the heaviest coffee drinkers (more than five cups a day), who had a 12 percent lower death risk than nondrinkers.

“The body of evidence does suggest coffee can fit into a healthy lifestyle,” Hu said.

That evidence, Hu noted, has already been incorporated into the latest U.S. dietary guidelines, which say that a healthy diet can include up to three to five cups of coffee a day.

But overall lifestyle is key, Hu said. That is, there’s a difference between a person who gets little sleep, then uses coffee to function during the day, and a person who sleeps well, exercises, and eats a balanced diet that includes some coffee.

Alice Lichtenstein, a spokesperson for the American Heart Association, agreed.

“This doesn’t mean you should start drinking coffee in the hopes of getting health benefits,” said Lichtenstein, who is also a professor of nutrition science and policy at Tufts University in Boston.

But, she added, the new findings build on years of evidence that coffee is not the bad guy many believe it is. “There’s this lingering idea that coffee must be bad for you because it’s enjoyable,” Lichtenstein said. “It’s almost like we’ve been trying to find something wrong with it.”

There are caveats, though. “You do need to be careful about what you’re putting in your coffee,” Lichtenstein pointed out. Some milk is fine, she said, but watch the sugar and heavy cream.

And why would coffee be related to health benefits? It’s not clear from this study, Hu said, but other research has suggested that compounds in coffee can reduce inflammation, act as antioxidants, and improve blood sugar regulation, among other things.

Also, when it comes to some neurological conditions, such as Parkinson’s disease, Hu said, there’s evidence that caffeine offers benefits.

SOURCES: Frank Hu, M.D., Ph.D., professor, nutrition and epidemiology, Harvard School of Public Health, Boston; Alice Lichtenstein, D.Sc., professor, nutrition science and policy, Tufts University, Boston; Nov. 16, 2015, Circulation, online

Read more at http://www.philly.com/philly/health/HealthDay705311_20151116_Coffee_Drinkers_May_Live_Longer.html#rPogcDb2tVXwEFwz.99

New scientific evidence that intermittent fasting has health benefits

On By A.P.In fastingLeave a comment

by Charles Q. Choi

Instead of eating three square meals a day, an eating schedule that involves “intermittent fasting” could help fight not just obesity but many related diseases of modern life, such as diabetes, heart disease, cancer and Alzheimer’s, researchers say.

he advice given on fighting obesity usually focuses on consuming fewer calories and exercising more. The benefits of such foods as vegetables, fruits, nuts, fiber and fish, and the value of reducing or eliminating snacks are often also touted.

However, mounting evidence reveals that other key aspects of diet — when and how often people eat — can also play a major role in health. In fact, the most common eating pattern in modern societies of three meals daily, plus snacks, is abnormal from the perspective of human evolution, an international group of researchers wrote in an article published in the journal Proceedings of the National Academy of Sciences.

More and more research shows that intermittent fasting could have benefits, they said.

“Fasting alone is more powerful in preventing and reversing some diseases than drugs,” said Satchidananda Panda, an associate professor of regulatory biology at the Salk Institute for Biological Studies in San Diego, California, and one of the co-authors of the article.

Ancient hunter-gatherers often ate only intermittently, the researchers noted in their article. This suggests that the ability to function at a high level both physically and mentally during extended periods without food may have been crucial in human evolution, and that the human body may have adapted to perform at its best with intermittent fasting.

Such intermittent fasting could consist of eating 500 calories or less either two days each week, or every other day, or not eating breakfast and lunch several days each week, the researchers said.

Prior research suggests that in animals, intermittent fasting can fend off or even reverse such illnesses as cancer, diabetes, heart disease and neurodegenerative disorders. Animal studies suggest that intermittent fasting provides these benefits by allowing the body to respond better to stress that might otherwise damage it. For example, fasting could starve tumors, reduce inflammation, or improve the removal of damaged molecules and other components of cells, the researchers said.

“Intermittent fasting helps the body to rejuvenate and repair, thereby promoting overall health,” Panda told Live Science.

In addition, the body may respond better to meals eaten at some times of the day rather than others because of the body’s circadian rhythms. In the years before artificial light, people depended on natural patterns of day and night, with food primarily eaten during the day and fasting occurring at night. This means that eating at certain times of the day may be healthier for the body’s metabolism — for example, in 2013, two studies in humans suggested that eating meals earlier in the day improved weight loss in overweight and obese people.

Panda said that it may be challenging for people to fast intermittently, instead of eating three meals every day. Eating breakfast is often promoted as a weight-control aid, but recent evidence has suggested it might not be, the researchers said.

Future research needs to further explore the benefits and drawbacks of different types of intermittent fasting in a variety of populations. “Its effectiveness in both preventing and reversing diseases, as well as interaction with standard medications for chronic metabolic diseases, should be tested in appropriate volunteer groups,” Panda said.

http://www.livescience.com/48888-intermittent-fasting-benefits-weight-loss.html

Sleep or die — growing body of research warns of heart attacks, strokes

On By A.P.In Medicine, SleepLeave a comment

We have all experienced the aftermath of a bad night’s sleep: grogginess, irritability, difficulty carrying out even the simplest of tasks. A growing amount of research suggests that not getting enough shut-eye could also have insidious effects on heart disease, obesity and other conditions.

The American Academy of Sleep Medicine, the largest physician-based organization for sleep medicine, recently put out their first recommendations for what is the right amount of sleep. It advises that adults get at least seven hours every night based on research on the link between inadequate sleep and a number of poor health outcomes.

Although most of us already know that we should get at least seven hours of sleep, a study last month suggested that Americans are creeping down to that cutoff. The average amount of sleep that they reported getting a night has dropped from 7.4 hours in 1985 to 7.29 hours in 1990 to 7.18 in 2004 and 2012.

The Centers for Disease Control and Prevention, which requested and helped support the development of the current recommendations, has called not getting enough sleep a public health epidemic.

For many aspects of health, “it was quite clear that seven to nine hours was good,” said Dr. Nathaniel F. Watson, president of the American Academy of Sleep Medicine and a professor of neurology at University of Washington. Watson led the panel of experts that wrote the recommendations. The group looked at more than 300 studies.

Getting only six hours of sleep a night or less was associated with setbacks in performance, including mental alertness and driving ability, and increased risk of heart attack, stroke, diabetes and obesity, Watson said.

There were not enough studies looking at the health of people who got between six and seven hours of sleep or more than nine hours to know how their health fared.

The panel did not put an upper cutoff on the amount of sleep a person should get because, in addition to the lack of evidence, “there are instances where a person might sleep longer if they are recovering from a sleep debt or illness, and we had trouble coming up with a biological way that sleep would be bad for you,” Watson said.

Although there have been reports that sleeping nine hours or more a night is associated with increased risk of death, that link probably has more to do with the fact that the people who slept a lot had underlying illnesses that ultimately did them in, said James Gangwisch, a sleep researcher at Columbia University who helped develop the current recommendations.

In addition, reports of sleeping a lot may actually be an indicator that a person is not exercising or socializing, which can carry health risks.

Sleep and how it relates to body mass and more

The panel looked at studies that reported connections between the amount of sleep that people said they got and their health over long periods. The panel also took into consideration studies that monitored people in sleep labs that controlled how much sleep they got.

For example, Gangwisch and his colleagues have reported a connection between getting less than seven hours of sleep a night and high body mass index. Separate studies in sleep labs suggest how inadequate sleep could lead to obesity: it drives up the levels of appetite-inducing hormones.

The weight gain that might be caused by inadequate shut-eye could, in turn, increase the risk of heart attack and stroke, Gangwisch said. In addition, sleep deficits seem to increase blood pressure as several studies have found, which could be bad for heart health.

One small study found that healthy adults had higher blood pressure after a night when they were only allowed to sleep four hours compared with a night when they were allowed to sleep for eight hours.

It is hard to say, however, if depriving people of sleep for an extended period would have lasting effects on blood pressure and appetite, even though studies linking sleep deprivation with heart disease and weight gain suggest so.

Sleep lab studies usually only investigate the effect of abridged snoozing for several nights, but people might adjust somewhat to sleep deprivation if it became the norm for them, Gangwisch said.

Although the recent recommendations are for the appropriate amount of shut-eye, getting bad sleep could be just as harmful as not getting enough sleep. Among the most common sleep disorders are insomnia and obstructive sleep apnea, which causes people to stop breathing intermittently throughout the night. About 10% of adults have chronic insomnia; obstructive sleep apnea affects an estimated 24% of men and 9% of women.

Obstructive sleep apnea in particular can take a toll in many ways beyond just shortening the amount of sleep you get, Watson said. The condition can increase blood pressure (separately from the effect of not getting enough sleep), deprive the body of oxygen, cause irregular heartbeat and make the blood more sticky, all of which can increase the risk of heart disease and stroke, he said.

A study that was presented this week at the European Society of Cardiology meeting found that men who had a sleep disorder were between 2 and 2.6 times more likely to have a heart attack and 1.5 to 4 times more likely to have a stroke over the 14-year period of the study.

Not sleeping well? Talk to the doc

“This study underscores to me the importance that if a person doesn’t think they are sleeping well, they should talk to their doctor,” said Kristen Knutson, an assistant professor of medicine at the University of Chicago who was not involved in the study.

Signs that you are not sleeping well or enough include needing a lot of caffeine to get through the day and falling asleep during a meeting or movie, which Knutson said does not usually happen in well-rested people no matter how bored they are.

ome people might need more or less than seven hours of shut-eye. To know what is right for you, see how long you sleep when you are a couple of days into a vacation and the alarm does not go off, Knutson suggested. (The first couple of days you might sleep longer because you are catching up.)

Knutson agrees with the advice that there does not seem to be a danger in sleeping too much. “People generally don’t sleep more than they should, and if you are laying in bed and can’t sleep, the general recommendation is to get up,” she said.

There are a number of strategies for making the most of your slumber. These include going to sleep and waking up about the same time every day, making your bedroom dark and cool and avoiding caffeine too close to bedtime.

“Some people view sleep as an obstruction to success, and we would rather have people view it as a tool for success,” Watson said. “We really want people to prioritize their sleep and understand that it is as important to their overall well being as diet and exercise,” he added.

http://www.cnn.com/2015/06/19/health/sleep-or-die/index.html

Sitting too much may be twice as dangerous for your health as being obese.

On By A.P.In Health, Obesity1 Comment

There’s been a fast growing body of evidence in the last several years that lack of exercise – or sedentariness – is a major risk factor in health. It’s been linked to heart disease, cancer, and to an early death. And now, a new study finds that lack of exercise may actually be even more of a risk than obesity in early mortality: The researchers calculate that a sedentary lifestyle may actually confer twice the risk of death as being obese. That said, the two are both important and, luckily, closely related: So if you start getting active, you’ll probably lose a little weight along the way, which itself is a very good thing.

The new study looked at data from over 334,000 people who participated in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study. Over a period of 12 years, the participants’ height, weight, and waist circumferences were tracked, along with self-reports of activity levels, both at work and in free time. All-cause mortality (i.e., death from any cause) was the main outcome of interest.

It turned out that lack of physical activity was linked to the greatest risk of death – and the greatest reduction in death risk was in the difference between the lowest two activity groups. In other words, just moving from “inactive” to “moderately inactive” showed the largest reduction in death risk, especially for normal weight people, but true for people of all body weights. And, the authors say, just taking a brisk 20-minute walk per day can move you from one category to the other, and reduce the risk of death anywhere from 16% to 30%.

Using a statistical model, the team also calculated that being sedentary may account for double the death risk of obesity. According to their math, of the 9.2 million deaths in Europe in 2008, about 337,000 were attributable to obesity, whereas 676,000 were attributable to sedentariness.

Another takeaway from the study, however, is that waist circumference is a bigger player in mortality risk than overall body weight, which has certainly been suggested by previous studies. Belly fat seems to be disproportionately linked to chronic health issues like heart disease, stroke, diabetes, cancer, and of course, early mortality. So reducing belly fat is always a significant benefit to one’s health.

“This large study is rather complex in its details, but the take-away messages are actually both clear and simple,” says David L, Katz, Director of the Yale University Prevention Research CenterGriffin Hospital. “At any given body weight, going from inactive to active can reduce the risk of premature mortality substantially. At any given level of activity, going from overweight to a more optimal weight can do the same. We have long known that not all forms of obesity are equally hazardous, and this study reaffirms that. Losing weight if you have an excess around the middle, where it is most dangerous, exerts an influence on mortality comparable to physical activity. Losing excess weight that is not associated with a high waist circumference reduces mortality risk, but less — as we would expect.”

But perhaps the main point in all of this is that being active and being a healthy weight are inextricably linked. Though activity by itself can offer an immediate health benefit if you remain overweight, getting active also leads naturally to loss of body weight. “This study reminds that being both fit and unfat are good for health,” says Katz, “and can add both life to years, and years to life. These are not really disparate challenges, since the physical activity that leads to fitness is on the short list of priorities for avoiding fatness as well. The challenge before us now is for our culture to make it easier to get there from here.”

Earlier this month a study showed that the concept of “healthy obesity” may be very misleading, since health markers in an obese person tend to deteriorate over time. Though the current study suggests that fitness may matter more than fatness, the two are really two sides of a coin: It would be silly to become active and not lose weight — and it would be very hard to do, since the one leads to the other. But perhaps given the great benefits of exercise alone, public health campaigns should focus not just on losing weight, but on encouraging people to add just small amounts physical activity to their lives right off the bat, and to see where it goes from there.

http://www.forbes.com/sites/alicegwalton/2015/01/15/is-lack-of-exercise-worse-for-your-health-than-obesity/

How stress can clog your arteries

On By A.P.In Anxiety, cardiovascular disease, Dr. Rajadhyaksha, heart attack, high blood pressure, high cholesterol, hypercholesterolemia, hypertension, immune system, Medicine, myocardial infarction, Nature Medicine, Sarah C. P. Williams, Science, stress1 Comment

By Sarah C. P. Williams

There’s a reason people say “Calm down or you’re going to have a heart attack.” Chronic stress—such as that brought on by job, money, or relationship troubles—is suspected to increase the risk of a heart attack. Now, researchers studying harried medical residents and harassed rodents have offered an explanation for how, at a physiological level, long-term stress can endanger the cardiovascular system. It revolves around immune cells that circulate in the blood, they propose.

The new finding is “surprising,” says physician and atherosclerosis researcher Alan Tall of Columbia University, who was not involved in the new study. “The idea has been out there that chronic psychosocial stress is associated with increased cardiovascular disease in humans, but what’s been lacking is a mechanism,” he notes.

Epidemiological studies have shown that people who face many stressors—from those who survive natural disasters to those who work long hours—are more likely to develop atherosclerosis, the accumulation of fatty plaques inside blood vessels. In addition to fats and cholesterols, the plaques contain monocytes and neutrophils, immune cells that cause inflammation in the walls of blood vessels. And when the plaques break loose from the walls where they’re lodged, they can cause more extreme blockages elsewhere—leading to a stroke or heart attack.

Studying the effect of stressful intensive care unit (ICU) shifts on medical residents, biologist Matthias Nahrendorf of Harvard Medical School in Boston recently found that blood samples taken when the doctors were most stressed out had the highest levels of neutrophils and monocytes. To probe whether these white blood cells, or leukocytes, are the missing link between stress and atherosclerosis, he and his colleagues turned to experiments on mice.

Nahrendorf’s team exposed mice for up to 6 weeks to stressful situations, including tilting their cages, rapidly alternating light with darkness, or regularly switching the mice between isolation and crowded quarters. Compared with control mice, the stressed mice—like stressed doctors—had increased levels of neutrophils and monocytes in their blood.

The researchers then homed in on an explanation for the higher levels of immune cells. They already knew that chronic stress increases blood concentrations of the hormone noradrenaline; noradrenaline, Nahrendorf discovered, binds to a cell surface receptor protein called β3 on stem cells in the bone marrow. In turn, the chemical environment of the bone marrow changes and there’s an increase in the activity of the white blood cells produced by the stem cells.

“It makes sense that stress wakes up these immune cells because an enlarged production of leukocytes prepares you for danger, such as in a fight, where you might be injured,” Nahrendorf says. “But chronic stress is a different story—there’s no wound to heal and no infection.”

In mice living with chronic stress, Nahrendorf’s team reported today in Nature Medicine, atherosclerotic plaques more closely resemble plaques known to be most at risk of rupturing and causing a heart attack or stroke. When the scientists blocked the β3 receptor, though, stressed mice not only had fewer of these dangerous plaques, but also had reduced levels of the active immune cells in their plaques, pinpointing β3 as a key link between stress and atheroscelerosis.

The finding could lead to new drugs to help prevent cardiovascular disease, suggests biologist Lynn Hedrick of the La Jolla Institute for Allergy and Immunology in San Diego, California. “I think this gives us a really direct hint that the β3 receptor is important in regulating the stress-induced response by the bone marrow,” Hedrick says. “If we can develop a drug that targets the receptor, this may be very clinically relevant.”

More immediately, the new observations suggest a way that clinicians could screen patients for their risk of atherosclerosis, heart attack, and stroke, Tall says. “Rather than asking four questions about stress levels, we could use their white blood cell counts to monitor psychosocial stress,” he says.

Thanks to Dr. Rajadhyaksha for bringing this to the attention of the It’s Interesting community.

http://news.sciencemag.org/biology/2014/06/how-stress-can-clog-your-arteries