Is there a direct link between irregular heart rhythm and dementia risk?

Scientists found the risk to be higher in healthier adults under the age of 65.

ISLAMABAD, (ONLINE) - New research shows that people with AFib may have a higher risk of developing dementia. 

Atrial fibrillation is the most common type of arrhythmia, affecting about 46.3 million people globally.

Previous research is unclear about whether or not AFib is a direct risk factor for cognitive decline and dementia or whether observed increases in dementia are indirectly due to increased strokes from AFib.

Researchers have found that people with newly-diagnosed AFib have a modestly elevated risk of developing dementia whether or not they had a stroke from AFib.

Scientists found the risk to be higher in healthier adults under the age of 65.

Atrial fibrillation (AFib) — a type of arrhythmia causing an irregular heart rhythm — affects about 46.3 million people around the world.

Previous research supports AFib as a potential risk factor for cognitive declineTrusted Source and dementia.

Now, researchers from the University of Washington School of Medicine add to this body of research through a new study, finding that people with newly-diagnosed AFib have a modestly elevated risk of developing dementia.

Scientists also found this risk to be higher in younger adults under the age of 65 and those without chronic kidney disease.

The study was recently published in the Journal of the American Heart Association.

What is atrial fibrillation?

AFib is the most common type of heartbeat issue. It occurs when the heart’s two upper chambers — known as the atria — go out of sync, causing an abnormal heart rhythm. This, in turn, affects how well blood flowsTrusted Source from the atria to the lower chambers of the heart, called the ventricles.

Symptoms of AFib include:

heart palpitations

a fluttering feeling in the chest and/or angina-type chest pain in those with pre-existing heart disease

extreme tiredness

dizziness and/or fainting

shortness of breath

AFib can happen at any age. However, it is more common among older adults.

There is currently no cure for AFib. However, doctors can treat the conditionTrusted Source with medications and surgical procedures as needed.

People with AFib are at a higher risk for developing stroke, blood clots, and heart failure.

According to Dr. Nisha Bansal, a professor and the Arthur Stach Family Endowed Professor in the Division of Nephrology at the University of Washington School of Medicine and corresponding author of this study, it is well known that atrial fibrillation may lead to strokes, yet associations with other complications are less recognized.

“Biologically it seems plausible that atrial fibrillation may be linked with other important neurological complications, even in the absence of strokes, which motivated this study,” she told Medical News Today.

“Previous studies on the association of atrial fibrillation with dementia have yielded conflicting results, with some studies reporting a strong association and others demonstrating no association. We designed the present study to try to address some of the limitations of prior studies,” Dr. Bansal continued.

In this study, researchers analyzed health data from almost 200,000 adults in California.

Upon analysis, scientists found an average of 2.79 diagnoses of dementia occurred among 100 people over one year with AFib, compared to 2.04 diagnoses in people without over the same time period. All told, people with AFib had a 13% higher risk of developing dementia.

Additionally, Dr. Bansal and her team found adults under the age of 65 had a 65% higher dementia risk compared to adults 65 and older. And people without chronic kidney disease had a 14% higher risk for dementia than those with the condition.

“With this approach, we were not surprised to find this somewhat modest association between incident atrial fibrillation and risk of dementia,” Dr. Bansal explained.

“The findings in the subgroups were of particular interest — we found that the association of atrial fibrillation with risk of dementia was stronger in patients who were younger and those without kidney disease. We did not find differences by sex, race, or ethnicity.” — Dr. Nisha Bansal

When discussing dementia risks with people, Dr. Bansal said these findings support the need for doctors to provide a broader discussion of possible complications related to atrial fibrillation, particularly when making decisions related to therapies.

And she said right now they see two important next steps in this research.

“First, we hope to investigate the mechanisms that may explain this association further. Second, we hope to study the effects of treating atrial fibrillation on (the) subsequent risk of dementia,” Dr. Bansal said.

How does AFib heighten dementia risk?

Medical News Today also spoke with Dr. Shephal Doshi, a cardiac electrophysiologist and director of cardiac electrophysiology and pacing at Providence Saint John’s Health Center in Santa Monica, California, about this study.

He said we do not know yet how AFib might heighten a person’s dementia risk.

“There’s a lot of proposed hypotheses on how this could happen. We know patients with atrial fibrillation have a higher risk of stroke, and (they) could be having small mini-strokes, which can lead to vascular dementia,” Dr. Doshi explained.

“There’s also a theory that in atrial fibrillation, your heart doesn’t squeeze as well as it does with normal rhythm in many patients. In some patients, it seems to be okay, but is it potentially that you’re not getting as much blood flow to the brain? And over 100,000 heartbeats a day, day after day, year after year, does that accelerate someone having dementia?” — Dr. Shephal Doshi

Dr. Doshi said additional research should include the classification of different types of dementia and have a way to ensure people who are in the none-AFib category do not actually have undiagnosed AFib.

“I think most of us in the field that manage atrial fibrillation recognize all the potential bad outcomes that can come from atrial fibrillation, the majority of which involves having a stroke, having congestive heart failure,” he continued.

“People with AFib tend in general to not live as longTrusted Source as people who don’t have AFib. So this is just another piece of the puzzle that tells us that as our technology gets better, as we become better at managing AFib and treating AFib, that we work harder in trying to fix AFib,” he added.