Moderate drinking, possibly by dampening stress-related neurological signals, is associated with a significantly lower risk of dying from cardiovascular disease (CVD) when compared with abstainers or excessive drinkers, according to research at the American College of Cardiology’s 70th Annual Scientific Session, reports MedicalBrief. Three other studies — into exercise, having a spouse with CVD, and the effect of psychological distress — further highlighted the damaging role of stress in major heart events.
The study, based on the healthcare records of more than 53,000 people, is the first to show that drinking moderately — defined as no more than one alcoholic drink for women and two for men per day — may be heart protective, said Dr Kenechukwu Mezue, a fellow in nuclear cardiology at Massachusetts General Hospital and the study’s lead author. Findings should spur the search for new therapies, like exercise or yoga, that help lower stress and impact the heart without the drawbacks of alcohol.
“We found that stress-related activity in the brain was higher in non-drinkers when compared with people who drank moderately, while people who drank excessively (more than 14 drinks per week) had the highest level of stress-related brain activity,” said Mezue. “The thought is that moderate amounts of alcohol may have effects on the brain that can help you relax, reduce stress levels and, perhaps through these mechanisms, lower the incidence of cardiovascular disease.”
“While the current study suggests that moderate alcohol intake beneficially impacts the brain-heart connection, alcohol has several important side effects, including an increased risk of cancer, liver damage and dependence, so other interventions with better side effect profiles that beneficially impact brain-heart pathways are needed,” Mezue said.
For the alcohol study, data were obtained from the Mass General Brigham Biobank health care survey of 53,064 participants, of which 59.9% were women and the average age was 57.2 years. Alcohol intake was based on self-report and was classified as low (<1 drink/week), moderate (1-14 drinks/week) or high (>14 drinks/week). Major adverse cardiovascular events, including heart attack, stroke or related hospitalisations, were determined using diagnostic (ICD) codes.
Of the patients included, 752 underwent 18F-fluorodeoxyglucose positron emission tomography, or PET imaging, which is often used as part of cancer screening but can also show areas in the brain that have increased activity. The scans allowed researchers to objectively measure activity in regions of the brain known to be associated with stress. Researchers assessed stress-related brain activity by measuring the activity of the amygdala (the part of the brain associated with fear and stress) and dividing it by activity in the frontal cortex (the part of the brain involved in executive functions). They then grouped patients based on the extent of brain stress activity.
Of the 53,064 participants, 7,905 (15%) experienced a major adverse cardiovascular event: 17% in the low alcohol intake group and 13% in the moderate alcohol intake group. People who reported moderate alcohol intake were found to have a 20% lower chance of having a major event compared to low alcohol intake (in adjusted analysis), and also had lower stress-related brain activity. This remained significant even after controlling for demographic variables, cardiovascular risk factors, socioeconomic variables and psychological factors.
“Previous studies by our group and others have shown a robust association between heightened amygdalar activity and a higher risk of major adverse cardiovascular outcomes, such as heart attack, stroke or death. In the current study, path analyses showed that the link between moderate alcohol intake and lowered cardiovascular event risk is significantly mediated though reductions in amygdalar activity,” Mezue said.
The study is limited due to the self-reporting of alcohol intake based on the average consumption of drinks per week. The data is also from a single center, and each participant in the imaging sub-study only received a single brain scan. Further study would be needed to show that the observed reductions in brain activity are the direct result of moderate alcohol intake through repeated brain scans and more detailed alcohol intake assessments over time.
Previous research has indicated that moderate drinking could slow cognitive decline, protecting against dementia.
In a related study by the same research team led by Mezue, exercise was found to have a similar effect on brain activity as well as on the incidence of cardiovascular disease and events. The authors said exercise is associated with decreased stress-associated brain activity in a dose-dependent manner. While the connection between stress and heart disease is widely accepted, the authors said relatively little research has been done on how modifying stress may help protect heart health.
Also at ACC:2021, a China study found that individuals, especially men, living with a spouse with cardiovascular disease were more than twice as likely to have cardiovascular disease themselves. “In addition to sharing lifestyle factors and socioeconomic environment, our study suggests the stress of caring for a spouse with cardiovascular disease may contribute to increased cardiovascular risk.” The prominent role of women in determining a family's diet could also help explain the findings.
Researchers surveyed more than 5,000 heterosexual couples over the age of 45 living in seven regions of China from 2014-2016. Among men whose wives had cardiovascular disease, 28% had cardiovascular disease themselves, compared to 12.8% of men whose wives did not have cardiovascular disease. A man's likelihood of cardiovascular disease was highest if his wife had a history of stroke, obesity or smoking.
Among women whose husbands had cardiovascular disease, 21% had cardiovascular disease themselves, compared to just 9% of women whose husbands did not have cardiovascular disease. A woman's likelihood of cardiovascular disease was highest if her husband had a history of stroke.
Adults who reported severe psychological distress — such as depression or anxiety — after suffering a heart attack were more than twice as likely to suffer a second cardiac event within five years compared with those experiencing only mild distress.
The study is the first to comprehensively assess how mental health influences the outlook for younger (aged 18-61) heart attack survivors, according to the researchers. The study tracked inflammatory markers that appear to have a role in increasing cardiovascular risk among people experiencing distress. The findings align with previous studies focusing on older adults, bolstering the evidence for mental health as an integral part of a person's recovery after a heart attack.
“Our findings suggest that cardiologists should consider the value of regular psychological assessments, especially among younger patients," said Dr Mariana Garcia, a cardiology fellow at Emory University in Atlanta and the study's lead author. "Equally importantly, they should explore treatment modalities for ameliorating psychological distress in young patients after a heart attack, such as meditation, relaxation techniques and holistic approaches, in addition to traditional medical therapy and cardiac rehabilitation."
The researchers analysed health outcomes in 283 heart attack survivors between the ages of 18 and 61, with an average age of 51 years. Study participants completed a series of validated questionnaires measuring depression, anxiety, anger, perceived stress and post-traumatic stress disorder within six months of their heart attack. Based on these questionnaires, the researchers established a composite score of psychological distress for each participant and grouped patients based on experiences of mild, moderate and high distress.
Within five years after their heart attack, 80 of the 283 patients suffered a subsequent heart attack or stroke, were hospitalised for heart failure or died from cardiovascular causes. These outcomes occurred in nearly half (47%) of patients experiencing high distress compared to 22% of those experiencing mild distress.
Previous studies suggest inflammation is one mechanism through which psychological distress may lead to heart problems. In the new study, patients who experienced high distress were also found to have higher levels of two inflammatory markers — interleukin-6 and monocyte chemoattract protein-1 — in their blood during rest and after mental stress. These markers, which increase during times of mental stress, are known to be associated with plaque buildup in the arteries and adverse cardiac events.
“It is thought that those who have had a heart attack may be particularly vulnerable to plaque rupture as a result of these inflammatory mechanisms at play," Garcia said. “The association we found was independent of known cardiovascular risk factors and suggests mechanisms involving systemic inflammation in response to stress may be implicated in the likelihood of a subsequent cardiac event.”
The researchers also found that patients with high distress were more often Black, female and from a disadvantaged socioeconomic background and were more likely to smoke or have diabetes or high blood pressure.
“This finding highlights the importance of socioeconomic status in regard to higher distress and raises important questions about the role of race, sex and other factors,” Garcia said.
The researchers plan to further investigate how socioeconomic and demographic factors may influence mental health among people who suffer a heart attack at a young age. Recent studies have suggested younger adults, especially women, account for an increasing proportion of the heart attacks occurring each year in the US, Garcia said, underscoring the importance of improving outcomes in this population.
“Outreach to the community has led to increased awareness of traditional heart disease risk factors and focus on things like diet and exercise, but many people, particularly younger people, may not be aware of the importance of mental health," Garcia said. "Our study offers a strong message to people recovering from a heart attack that ameliorating psychological distress is equally important.”
Garcia cautioned that causation cannot be proven with an observational study and noted the possibility of recall bias among people with more severe disease, since psychological distress was self-reported in this study. While the study's sample size was relatively small, it did demonstrate a robust association using a prospective design.
Alcohol’s Beneficial Effect on Cardiovascular Disease is Partially Mediated through Modulation of Stress-Associated Brain Activity, as well as the related study on exercise;
Association of Spousal Health Status and Cardiometabolic Risk Factors with Cardiovascular Disease and Diabetes Mellitus in China;
Psychological Distress and Risk of Adverse Cardiovascular Outcomes in Young and Middle-Aged Survivors of Myocardial Infarction
are not, at the time of publication (12 May 2021) available online.
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