People with atrial fibrillation (AF) are at an increased risk of dementia, according to new research.
AF is a common heart condition characterised by an irregular heartbeat and is a leading cause of stroke.
AF symptoms can come and go and many people are unaware that they have the condition.
While AF is known to increase stroke risk and stroke exacerbate dementia, the connection between AF and dementia with no incidence of stroke had not previously been established.
Lina Rydén, who has a PhD in neuropsychiatric epidemiology at Sahlgrenska Academy, University of Gothenburg, based her thesis on data from the Gothenburg H70 Birth Cohort (H70) studies.
The research included data on 70-year-olds examined in 2000 who were then monitored up until the age of 82 to see who developed dementia.
Another cohort of 70-year-olds was examined in 2014, with MRI performed to detect structural changes in the brain.
As well as elevated dementia and stroke risk, Rydén discovered that people with AF have silent brain infarcts and small infarcts deeper inside the white matter of the brain, more frequently than others.
These small infarcts, called lacunas, may be signs of cerebral small vessel disease.
Rydén said:
“There may be several reasons why the risk of dementia is elevated in people with arial fibrillation, even if they don’t get a stroke.
“Dementia may be caused by, for example, altered blood flow to the brain; silent brain infarcts, which are lesions in the brain that are visible on brain imaging but don’t cause any typical stroke symptoms; or AF triggering an inflammatory process that raises dementia risk.
“The fact that AF also causes small infarcts deeper inside the white matter of the brain may mean that AF causes not only stroke and silent infarcts due to blood clots that migrate from the heart and attach themselves to the vessels of the brain, but that other mechanisms resulting in oxygen deficiency can affect the brain in AF.
“But to understand more specifically how AF affects the brain requires more research.”
Current treatment of AF focuses on mitigating symptoms and preventing stroke.
However, more research is needed to establish the best course of treatment to reduce dementia risk, Rydén added.
