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A new study investigates the links between heart health and brain health. Tomasz Bobrzynski (tomanthony)/Getty Images
  • A recent study looked at heart health and cognitive function in more than 29,000 people living in the United Kingdom.
  • Those with a healthy heart structure and function performed significantly better in cognitive ability tests than those with a less healthy heart structure and function.
  • The observed associations between brain and heart health remained significant after adjustment for a range of cardiometabolic, lifestyle, and demographic factors.

Past research suggests a strong association between cardiovascular disease and dementia. For example, one large, long-term study from 2017 showed that middle-aged individuals with risk factors for heart disease — smoking, obesity, or a diagnosis of diabetes or hypertension — are also at increased risk for dementia.

Now, a group of researchers claims to be the first to demonstrate with a large group of healthy people that individuals with healthier hearts have better cognitive performance.

The authors, who are affiliated with the University of São Paulo in Brazil and several U.K. institutions — Queen Mary University of London, the University of Oxford, Imperial College London, and the University of Southampton — recently published their findings in the journal European Heart Journal Cardiovascular Imaging.

“Our findings are highly relevant in an ever-aging global population, with an ever-increasing burden of common chronic diseases, such as ischemic heart disease and dementia,” Dr. Zahra Raisi-Estabragh, an author of the study and British Heart Foundation Clinical Research Training Fellow at Queen Mary University of London, explained to Medical News Today.

“Understanding links between these diseases enables us to optimize our assessment of older people and to potentially develop new therapies, which will target common mechanisms of aging.”

The researchers used data from 29,763 participants from the U.K. Biobank, a biomedical database containing in-depth genetic and health information from half a million participants. The average age of the participants was 63 years. Overall, the participants were healthier and wealthier than the national average in the U.K.

For the study, the researchers assessed heart health by examining cardiac MRI scans of participants, while they assessed cognitive function with fluid intelligence tests. These cognitive tests measure an individual’s capacity to solve problems using logic and reasoning rather than previously learned knowledge. The researchers also tested reaction time.

The researchers found associations between better cognitive performance and measures that likely represent a healthier heart. These measures include larger ventricular cavity volumes, larger left ventricular and right ventricular stroke volumes, higher left ventricular mass, and greater aortic distensibility.

Reduced cognitive function was associated with smaller ventricular volumes and lower left ventricular mass, together with smaller left ventricular and right ventricular stroke volumes and lower aortic compliance.

Participants with higher distensibility — less stiffness in the artery, which indicates better health — showed less rapid age-related decline in fluid intelligence.

The researchers observed associations between brain and heart health that remained significant even after adjustment for a range of cardiometabolic, lifestyle, and demographic factors.

Dr. Scott Kaiser, a geriatrician and director of geriatric cognitive health for the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, CA, was not involved in the study. He told MNT that he frequently sees patients experiencing both heart disease and dementia.

“We know that there’s a close correlation between heart health and brain health. That is no surprise,” Dr. Kaiser said. “What was really cool about this study is that […] it just gave a little bit more of a robust picture. It was a large sample of biomarkers [that allowed the researchers] to really look at what was going on in terms of the heart health in a robust way, and then matched it with some pretty cool cognitive health markers. So it just kind of filled out the picture a little.”

The mechanisms behind the association between cardiovascular disease and dementia are not well-understood, the researchers explain in their paper.

“Although previous work had mostly attributed links between brain and heart health to classical vascular risk factors (smoking, high blood pressure, high cholesterol), our findings suggest that relationships between the two organs are not adequately explained by these shared risk factor[s],” Dr. Raisi-Estabragh told MNT.

In their study, the researchers question whether both reduced brain and cardiovascular health could be a consequence of accelerated multisystem aging. Additionally, the researchers consider the possibility of “alternative disease mechanisms” contributing to an association between heart and brain health.

They point to another study that showed that brain protein fragments called beta-amyloid, which are abnormally deposited in the brain in Alzheimer’s disease, may also be deposited in the muscular tissue of the heart.

The researchers stress that the study does not show that heart disease causes impaired cognition or vice versa. As this is an observational study, the researchers are not able to make a definitive inference about causality. “Understanding the precise mechanisms requires further research,” Dr. Raisi-Estabragh explained to MNT.

Dr. Kaiser is hopeful that the study will prompt more work. “Somebody needs to actually look at a cellular level about these amyloid concerns and whatnot and understand what’s happening,” he said.

Indeed, Dr. Raisi-Estabragh plans to continue studying the links between heart health and cognitive function.

“We are interested in understanding the interconnected relationship between health across different organ systems and how these may be modified by environmental, behavioral, and health factors,” she told MNT.