This heart abnormality can raise your risk for dementia - study

An abnormality in the heart's left atrium known as atrial cardiopathy is already linked to stroke and atrial fibrillation, but it may be independently linked to dementia as well.

Virtual image of human heart  (photo credit: ING IMAGE/ASAP)
Virtual image of human heart
(photo credit: ING IMAGE/ASAP)

Can this heart problem increase one's risk of dementia? According to a new study, a certain abnormality in the heart's left atrium known as atrial cardiopathy can give one a 35% higher risk of developing dementia later in life.

The findings of this study were published in the peer-reviewed academic periodical Journal of the American Heart Association.

The study sheds light on a previously overlooked factor in raising the risk of developing dementia.

Background: What is dementia?

Dementia is a neurological condition that is best defined as a loss of cognitive function, meaning impairment in one's ability to think, remember and reason

 Alzheimer's disease (illustrative). (credit: VIA WIKIMEDIA COMMONS) Alzheimer's disease (illustrative). (credit: VIA WIKIMEDIA COMMONS)

Dementia can also cause other symptoms such as difficulties in controlling emotions, strange choices in words, sparking paranoia or delusions, a sense of apathy and difficulty moving or maintaining balance.

This impairment is of such significant severity that it affects one's ability to carry out their daily life.

This condition itself is very diverse and covers a wide range of severity, with there being different forms of dementia.

The most common of these forms is Alzheimer's disease, though other forms also exist, and it is possible to have multiple types of dementia at once.

While there are methods in place to help manage dementia to the best of one's ability and some measures do exist to try and reduce any possible risk factors, there are currently no cures or proven prevention methods for any form of dementia.

Overall, dementia becomes increasingly more common as one gets older. According to the National Institute on Aging (NIA), part of the US National Institutes of Health (NIH), about one-third of all people at the age of 85 or over have some form of dementia.

However, despite how common it is, dementia is very much not a normal and natural part of the aging process. Indeed, while loss of neurons in the brain as one ages is universal, dementia is something else altogether.

A number of risk factors do exist that can help contribute to one's risk in developing dementia. However, scientists may now have identified a new one.

 Stroke (illustrative) (credit: INGIMAGE) Stroke (illustrative) (credit: INGIMAGE)
Listen to your heart: You may be at increased risk for dementia

In order to understand what the study found in the heart that can contribute to a rise in one's risk of developing dementia, it's important to explain a bit about the heart and how it works.

The heart is one of the most important organs in the body, responsible for pumping blood.

The heart itself also has four chambers, two upper ones and two lower ones. The lower chambers are the left and right ventricles, which are responsible for pumping blood out of the heart. The upper chambers are the left and right atria (plural of atrium), which are responsible for receiving incoming blood.

Essentially, the atria take in blood that comes in from the lungs and them pump it into the ventricles. The ventricles then pump the blood back out into the body.

But sometimes, there are abnormalities in the left atrium, either in its structure or functioning. This condition is known as atrial cardiopathy.

This condition itself is already thought to contribute to the risk of other conditions such as thromboembolisms, atrial fibrillation and strokes.

In particular, the latter of these two conditions are both factors that have been linked to a higher risk of dementia.

But this raises the question: Is atrial cardiopathy only linked to dementia through stroke and atrial fibrillation? Or, rather, is it possible that the link between dementia and atrial cardiopathy is something independent?

That is what this study sought to examine.

Dementia and the heart: What's the link?

To answer this, the scientists, led by John Hopkins University School of Medicine assistant professor of neurology Michelle C. Johansen, examined participants that were part of an over 15,000-strong group of participants recruited for the Atherosclerosis Risk in Communities study that had been going on since 1987 to study heart health in communities throughout the US.

Each participant was between the ages of 45 and 65 and hailed from rural and urban areas in the US.

Already, this has helped lead to several other discoveries in studies on a number of conditions like heart disease, stroke and diabetes.

The current group of participants numbered 5,078 people, 59% female and 41% male and at this point were at the average age of 75.

To study them, the participants were evaluated with a neuropsychological test battery on Alzheimer's Disease from the NIA and were also given interviews and other tests needed, all in order to better determine if they could be diagnosed with dementia.

In addition, tests were also done on the heart, specifically to check the size and functionality of the heart's left atrium and to spot any possible signs of atrial cardiopathy.

And in total, 763 people had developed dementia, while 1,709 people had atrial cardiopathy.

So this definitely seems to be associated with some sort of increased risk, 35% to be specific. But what about stroke and atrial fibrillation? How did that effect the numbers? After all, not everyone with atrial cardiopathy had a stroke or atrial fibrillation.

According to the data, those two conditions were still associated with an increased risk, but it wasn't too significant, being associated with 28% and 31% increased risk respectively. 

And with atrial cardiopathy alone having a higher risk, it seems that the link between it and dementia may be a risk factor all on its own.