Adults – ages 45 or older who experience psychological distress such as depression and anxiety – may have an increased risk of developing cardiovascular disease, according to new research in Circulation: Cardiovascular Quality and Outcomes, an American Heart Association journal.
In a study of 221,677 participants from Australia, researchers found that:
- Among women, high/very high psychological distress was associated with a 44 percent increased risk of stroke; and
- In men ages 45 to 79, high/very high versus low psychological distress was associated with a 30 percent increased risk of heart attack, with weaker estimates in those 80 years old or older.
The association between psychological distress and increased cardiovascular disease risk was present even after accounting for lifestyle behaviors such as smoking, alcohol intake, dietary habits and disease history. “While these factors might explain some of the observed increased risk, they do not appear to account for all of it, indicating that other mechanisms are likely to be important,” said Caroline Jackson, Ph.D., the study’s senior author and a Chancellor’s Fellow at the University of Edinburgh in Edinburgh, Scotland.
The research involved participants who had not experienced a heart attack or stroke at the start of the study and who were part of the New South Wales 45 and Up Study that recruited adults ages 45 or older between 2006 and 2009. Researchers categorized psychological distress as low, medium and high/very high using a standard psychological distress scale which asks people to self-assess the level. Of the participants – 102,039 men – average age 62 – and 119,638 women – average age 60 – 16.2 percent reported having moderate psychological distress and 7.3 percent had high/very high psychological distress. During follow-up of more than four years, 4,573 heart attacks and 2,421 strokes occurred. The absolute risk – overall risk of developing a disease in a certain time period – of heart attack and stroke rose with each level of psychological distress.
Underestimating Psychological Stress
The findings add to the existing evidence that there may be an association between psychological distress and increased risk of heart attack and stroke. But they also support the need for future studies focused on the underlying mechanisms connecting psychological distress and cardiovascular disease and stroke risk and look to replicate the differences between men and women. Mental disorders and their symptoms are thought to be associated with increased risk of heart disease and stroke, but previous studies have produced inconsistent findings and the interplay between mental and physical health is poorly understood.
People with symptoms of psychological distress should be encouraged to seek medical help because, aside from the impact on their mental health, symptoms of psychological distress appear to also impact physical health, Jackson said. “We encourage more proactive screening for symptoms of psychological distress. Clinicians should actively screen for cardiovascular risk factors in people with these mental health symptoms.”
All factors analyzed in this research, apart from the outcomes of heart attack and stroke, were identified at the same point in time, which made it difficult for researchers to understand the relationship between psychological distress and variables such as unhealthy behaviors like smoking and poor diet. With that analysis approach, they may have underestimated the effect psychological distress has on the risk of heart attack and stroke.
Link Between Stress And Bad News
Feeling stressed or anxious makes people more able to process and internalize bad news, a recent UCL-led study reports. The Wellcome-funded research, published in The Journal of Neuroscience, reveals that a known tendency of people to take more notice of good news than bad news disappears when people feel threatened. “Generally, people are quite optimistic and we ignore the bad and embrace the good,” said co-lead author Dr. Tali Sharot, UCL Experimental Psychology. “This is indeed what happened when our study participants were feeling calm; but when they were under stress, a different pattern emerged. Under these conditions, they became vigilant to bad news we gave them, even when this news had nothing to do with the source of their anxiety.”
Previous studies have shown that people are more likely to incorporate information into their existing beliefs if the information is positive. Such optimism can be good for well-being and keep people motivated, but can be unhelpful when people underestimate serious risks, so the researchers were seeking to understand if the general human tendency to prioritize good news might vary depending on other conditions.
The study was conducted in two parts: one in a UCL lab, and one with firefighters in Colorado. In the lab, half of the 35 participants were told at the start that they would need to deliver a speech on a surprise topic in front of a panel of judges after completing a task – thus elevating their stress levels – while the other half were told they would complete an easy writing assignment at the end of the study. The heightened stress among those anticipating public speaking was confirmed by measures of physiological arousal by testing their skin conductance and cortisol levels and self-reported anxiety.
Optimistically Processing Information
The participants were asked to estimate the risk level of various threatening life events, such as being a victim of domestic burglary or credit card fraud. They were then told the real risk – either good news or bad news depending on how it compared to their estimate. Later they were asked to provide new estimates of what they thought the risks would be for themselves. As expected, the participants who were more relaxed internalized the good news better than the bad. Researchers found these participants continued to underestimate some risks even when being told the threatening event was more likely than they thought.
People who were stressed or anxious were better than the more relaxed participants at incorporating the bad news into their existing beliefs, while still responding normally to good news. The study was replicated with similar findings in a real-world setting with firefighters, who did the task online while they were on shift between calls at the station. Their anxiety was measured by self-report, and varied naturally due to their volatile work environment.
The findings help explain how people benefit from a generally optimistic way of processing information, while still taking heed of warning signs when under threat. “A switch that automatically increases or decreases your ability to process warnings in response to changes in your environment might be useful,” says co-lead author Dr. Neil Garrett. “Under threat, a stress reaction is triggered and it increases the ability to learn about hazards – which could be desirable. In contrast, in a safe environment it would be wasteful to be on high alert constantly. A certain amount of ignorance can help to keep your mind at ease.”
Sleep Stress: A Cure For Not Sleeping?
In today’s environment, demanding jobs and socio-economic factors lead to sleep deprivation. Sleep deprivation induces a tremendous amount of stress, and stress itself is one of the major factors responsible for sleep loss or difficulty in falling into sleep. Sleep loss is also associated with certain other diseases including obesity, cardiovascular diseases, depression, anxiety, and mania deficits.
Scientists with the Japanese sleep institute recently found that the active component rich in sugarcane and other natural products may reduce stress and help contribute to sound sleep. The research group led by Mahesh K. Kaushik and Yoshihiro Urade of the International Institute for Integrative Sleep Medicine, University of Tsukuba, found that octacosanol reduces stress and restores stress-affected sleep back to normal. Octacosanol is abundantly present in various everyday foods such as sugarcane, rice bran, wheat germ oil, and bee wax. The crude extract is policosanol, where octacosanol is the major constituent. Policosanol and octacosanol have already been used in humans for various other medical conditions.
In the study, authors made an advancement and investigated the effect of octacosanol on sleep regulation in mildly stressed mice by oral administration. Octacosanol reduced corticosterone level in blood plasma, which is a stress marker. The octacosanol-administered mice also showed normal sleep, which was previously disturbed due to stress. They therefore claim that the octacosanol mitigates stress in mice and restores stress-affected sleep to normal in mice. The sleep induced by octacosanol was similar to natural sleep and physiological in nature. However, authors also claimed that octacosanol does not affect sleep in normal animals.
These results demonstrated that octacosanol is an active compound that has potential to reduce stress and to increase sleep, and it could potentially be useful for the therapy of insomnia caused by stress. Octacosanol can be considered safe for human use as a therapy, because it is a food-based compound and believed to show no side effects. Octacosanol/policosanol supplements are used by humans for functions such as lipid metabolism, cholesterol lowering or to provide strength. However, well-planned clinical studies need to be carried out to confirm its effect on humans for its stress-mitigation and sleep-inducing potentials. “Future studies include the identification of target brain area of octacosanol, its BBB permeability, and the mechanism via which octacosanol lowers stress,” Kaushik says.
Reactive molecules derived from molecular oxygen – known as reactive oxygen species or ROS – increase dramatically in the body during times of environmental stress or disease. This stress can result in significant damage to cells and is associated with negative health consequences such as aging, male infertility, degenerative diseases and cancer. “We think there’s an ideal intermediate concentration, but neither extreme is good,” said Daniel Suter, a professor of biological sciences at Purdue University.
In a recent study published in The Journal of Neuroscience, Suter’s team looked at an enzyme that produces ROS in zebrafish embryos to see if it’s essential to the development of their nervous systems. Inhibiting this enzyme, NADPH oxidase or Nox, resulted in complications with signaling between the eyes and the brain. The research team used a drug called celastrol to inhibit Nox activity, which led to defects in the formation of the ganglion cell layer and optic nerve, both of which send signals from the retina of the eye to the brain.
Since a drug could affect other enzymes besides Nox, the researchers needed to confirm their results with another approach. The team turned to CRISPR, a system for modifying genes in living cells and organisms, to mutate Nox genes in the zebrafish embryo. This method also allowed the researchers to differentiate between different isoforms of Nox. Their findings show that Nox2 could be functionally important to neuronal development, whereas mutations in Nox5 could lead to more general developmental problems.
“This is really a study about the role of ROS as signaling molecules in normal development, but it has key applications for human health,” Suter said. “If you take too many antioxidants to treat disorders or injuries, you could go into a range where you get negative effects, because ultimately you need some ROS for normal signaling. We’re trying to figure out if there is a certain range that’s best.”