Have an Irregular Heartbeat? Dementia Risk Increased by 40 Percent

Scientists have found a link between an irregular heartbeat and the risk of developing dementia.

Atrial fibrillation, the most common type of heart arrhythmia, affects between 2.7 million and 6.1 million people in the U.S., according to the Centers for Disease Control and Prevention, a figure that is expected to rise as the population ages.

Because atrial fibrillation can cause blood to collect in the heart and clots to travel to the brain, the condition is already known to raise the risk of stroke.

File photo: Scientists have created human heart tissue that beats from stem cells. The engineered tissue could be used as a model of a human atrium (upper chamber), allowing researchers to test out new drugs as part of preclinical screening. Getty Images

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"In our study, we have shown a clear connection of atrial fibrillation with cognitive decline and dementia, while many previous studies have provided inconsistent results," Mozhu Ding, an author of the study and a Ph.D. candidate at the Karolinska Institutet's Aging Research Center in Sweden, told Newsweek.

The study, published in the journal Neurology, is the result of analysis of data on 2,685 people with an average age of 73. The participants did not have dementia at the start of the study, but 243 had atrial fibrillation. Researchers conducted interviews and medical examinations, which included thinking and memory skill tests, at the study's launch. Those 78 or younger were re-examined after six years, and volunteers 78 and above triennially.

By the study's end, 279 participants had developed atrial fibrillation, while 399 were diagnosed with dementia.

Patients with atrial fibrillation were 40 percent more likely to develop dementia and saw their cognitive abilities decrease more quickly than those who didn't have the heart condition.

But those who took blood thinners for their heart condition had a 60 percent lower risk of developing dementia. The same effects were not seen in those who took other blood-thinning medications, such as aspirin.

Ding acknowledged, "Our study is observational, and the results could be affected by different methodological issues. More research is needed to replicate our findings."

James Pickett, head of research at Alzheimer's Society, praised the study as "large" and "well executed."

"It is well established that what is good for your heart is good for your head, and this research adds even more weight to the relationship between heart health, stroke and vascular dementia risk, which are all affected by blood pressure and your circulatory system," he said.

Rosa Sancho, head of research at Alzheimer's Research UK, said she does not regard the study as particularly large but noted that "it highlights a stronger link to vascular dementia risk than to Alzheimer's disease, the most common form of the condition."

"In the study, treating an irregular heart rhythm with a blood-thinning drug was associated with a lower risk of dementia, but further research is needed to understand how anticoagulants could impact memory decline," she said. "Repurposing drugs currently used for other health conditions could radically accelerate the time it takes to find a life-changing dementia treatment, but we need to carefully consider the safety risks of any potential treatment."

Ding stressed that patients with irregular heartbeats should not be concerned by his team's findings. "It is very important for one to follow a healthy diet and lifestyle in order to prevent atrial fibrillation, which would in turn lower the risk of future dementia," he said. "For people with atrial fibrillation, it is important to follow the doctor's advice and take anticoagulants if necessary."

Earlier this week, a separate study revealed an association between air pollution and mouth cancer.

In research published in the Journal of Investigative Medicine, researchers in Taiwan found that pollutants—including PM2.5, tiny aerosols that can be inhaled into the lungs—heightened the chances of developing dementia.