The study shows that light to moderate drinking was associated with lower major adverse cardiovascular events (MACE), and this was partly mediated by decreased stress signaling in the brain.
In addition, the benefit of light to moderate drinking with respect to MACE was most pronounced among people with a history of anxiety, a condition known to be associated with higher stress signaling in the brain.
However, the apparent CVD benefits of light to moderate drinking were counterbalanced by an increased risk of cancer.
“There is no safe level of alcohol consumption,” senior author and cardiologist Ahmed Tawakol, MD, codirector of the Cardiovascular Imaging Research Center at Massachusetts General Hospital, Boston, said in an interview.
Dr. Ahmed Tawakol
“We see cancer risk even at the level that we see some protection from heart disease. And higher amounts of alcohol clearly increase heart disease risk,” Dr. Tawakol said.
The study was published online in the Journal of the American College of Cardiology.
Clear mechanistic link
Chronic stress is associated with MACE via stress-related neural network activity (SNA). Light to moderate alcohol consumption has been linked to lower MACE risk, but the mechanisms behind this connection remain unclear.
“We know that when the neural centers of stress are activated, they trigger downstream changes that result in heart disease. And we’ve long appreciated that alcohol in the short term reduces stress, so we hypothesized that maybe alcohol impacts those stress systems chronically and that might explain its cardiovascular effects,” Dr. Tawakol explained.
The study included roughly 53,000 adults (mean age, 60 years; 60% women) from the Mass General Brigham Biobank. The researchers first evaluated the relationship between light to moderate alcohol consumption and MACE after adjusting for a range of genetic, clinical, lifestyle, and socioeconomic factors.
During mean follow-up of 3.4 years, 1,914 individuals experienced MACE. Light to moderate alcohol consumption (compared to none/minimal) was associated with lower MACE risk (hazard ratio [HR], 0.786; 95% confidence interval [CI], 0.717-0.862; P < .0001) after adjustment for cardiovascular risk factors.
The researchers then studied a subset of 713 individuals who had undergone previous PET/CT brain imaging (primarily for cancer surveillance) to determine the effect of light to moderate alcohol consumption on resting SNA.
They found that light to moderate alcohol consumption correlated with decreased SNA (standardized beta, –0.192; 95% CI, –0.338 to 0.046; P = .01). Lower SNA partially mediated the beneficial effect of light to moderate alcohol intake on MACE risk (odds ratio [OR], –0.040; 95% CI, –0.097 to –0.003; P < .05).
Light to moderate alcohol consumption was associated with larger decreases in MACE risk among individuals with a history of anxiety (HR, 0.60; 95% CI, 0.50-0.72, vs. HR, 1.78; 95% CI, 0.73-0.80; P = .003).
The coauthors of an editorial say the discovery of a “new possible mechanism of action” for why light to moderate alcohol consumption might protect the heart “deserves closer attention in future investigations.”
However, Giovanni de Gaetano, MD, PhD, department of epidemiology and prevention, IRCCS NEUROMED, Pozzilli, Italy, one of the authors, emphasized that individuals who consume alcohol should not “exceed the recommended daily dose limits suggested in many countries and that no abstainer should start to drink, even in moderation, solely for the purpose of improving his/her health outcomes.”
Dr. Tawakol and colleagues said that, given alcohol’s adverse health effects, such as heightened cancer risk, new interventions that have positive effects on the neurobiology of stress but without the harmful effects of alcohol are needed.
To that end, they are studying the effect of exercise, stress-reduction interventions such as meditation, and pharmacologic therapies on stress-associated neural networks, and how they might induce CV benefits.
Dr. Tawakol said in an interview that one “additional important message is that anxiety and other related conditions like depression have really substantial health consequences, including increased MACE. Safer interventions that reduce anxiety may yet prove to reduce the risk of heart disease very nicely.”
The study was supported by the National Institutes of Health. Dr. Tawakol and Dr. de Gaetano have disclosed no relevant financial relationships.
A version of this article originally appeared on Medscape.com.