January 8, 2019
People with an irregular heartbeat known as atrial fibrillation are more likely to experience declines in thinking and memory skills with age and have a higher likelihood of developing dementia, according to a new report. But people who treat the heart rhythm disorder with blood thinners are less likely to develop dementia than their age-matched peers, the study found.
“Compromised blood flow caused by atrial fibrillation may affect the brain in a number of ways,” said study author Chengxuan Qiu of the Karolinska Institute and Stockholm University in Sweden. “We know as people age, the chance of developing atrial fibrillation increases, as does the chance of developing dementia. Our research showed a clear link between the two and found that taking blood thinners may actually decrease the risk of dementia.”
Some three million Americans have atrial fibrillation, or A-fib as it is commonly called. Many do not even know they have it. The condition is characterized by electrical irregularities in the heart’s upper chambers that cause them to contract abnormally and disrupt blood flow to the rest of the body.
People with A-fib are at high risk of having a stroke, because blood may thicken, forming clots that can enter the brain. To prevent strokes, doctors typically prescribe blood thinners, also known as anticoagulant drugs, such as warfarin.
Those with A-fib may have occasional palpitations in the chest, causing the heart to feel like it is poundin. They may also experience chest discomfort, shortness of breath, tiredness or dizziness. Or there may be no symptoms at all.
The condition is more common in men and tall people. High blood pressure, obesity, diabetes also predispose people to the condition. Many do not develop it until they are older. While A-fib can sometimes be detected with a standard EKG, you may have to wear a heart monitor for days to weeks to get a definitive diagnosis.
For the current study, researchers followed 2,685 participants whose average age was 73 for an average of six years. All participants were free of dementia at the start of the study, but 243 people, or 9 percent, had atrial fibrillation.
Through face-to-face interviews and medical exams, researchers gathered lifestyle and medical data on participants at the start of the study and during follow-up visits. All were screened for atrial fibrillation as well as for dementia and overall thinking and memory skills.
Over the course of the study, an additional 279 people, or 11 percent, developed atrial fibrillation, and 399, or 15 percent, developed dementia.
Researchers found that those who had atrial fibrillation had a faster rate of decline in thinking and memory skills than those without the condition. They were also 40 percent more likely to develop dementia.
Of the 2,163 people who did not have irregular heartbeat, 278 people developed dementia, or 10 percent. Of the 522 people with irregular heartbeat, 121 developed dementia, or 23 percent.
Researchers also found that people who took blood thinners for atrial fibrillation had a 60 percent decreased risk of dementia. Of the 342 people who did not take blood thinners for the condition, 76 people developed dementia, or 22 percent. Of the 128 people taking blood thinners, 14 developed dementia, or 11 percent. There was no decreased risk among people who took aspirin.
“Assuming that there was a cause-and-effect relationship between using blood thinners and the reduced risk of dementia, we estimated that about 54 percent of the dementia cases would have been hypothetically prevented if all of the people with atrial fibrillation had been taking blood thinners,” Dr. Qiu said. “Additional efforts should be made to increase the use of blood thinners among older people with atrial fibrillation.”
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Luciano A. Sposato and Lin Y Chen: “Reduced Risk of Dementia Among Patients With Atrial Fibrillation Receiving Oral Anticoagulants.” Neurology Vol. 91, October 2018
Mozhu Ding, Laura Fratiglioni, Kristina Johnell, et al: “Atrial Fibrillation, Antithrombotic Treatment, and Cognitive Aging: A Population-Based Study.” Neurology Vol. 91, October 2018.