“We cautiously suggest that an understanding of this relationship might provide a basis for new interventional strategies to help thwart the development of dementia,” the authors write.
The research, led by Michelle C. Johansen, MD, department of neurology, Johns Hopkins University, Baltimore, was published online in the Journal of the American Heart Association.
Atrial cardiopathy, characterized by abnormal size and function of the left atrium, has been associated with an increased risk of stroke and atrial fibrillation (AFib), and because both stroke and AFib are associated with an increased dementia risk, the authors write, it was important to investigate whether atrial cardiopathy is linked to dementia.
If that’s the case, they reasoned, the next question was whether that link is independent of AFib and stroke, and their new research suggests that it is.
For this analysis, the researchers conducted a prospective cohort analysis of participants in the Atherosclerosis Risk in Communities (ARIC) study who were attending visit 5 (2011-2013). During their fifth, sixth, and seventh clinical visits, the ARIC participants were evaluated for cognitive decline indicating dementia.
They studied a diverse population of 5,078 older adults living in four U.S. communities: Washington County, Md.; Forsyth County, N.C.; the northwestern suburbs of Minneapolis; and Jackson, Miss.
Just more than a third (34%) had atrial cardiopathy (average age, 75 years; 59% female; 21% Black) and 763 participants developed dementia.
Investigators found that atrial cardiopathy was significantly associated with dementia (adjusted hazard ratio, 1.35 [95% confidence interval, 1.16-1.58]).
They considered ARIC participants to have atrial cardiopathy if they had at least one of the following: P-wave terminal force greater than 5,000 mV·ms in ECG lead V1; NTproBNP greater than 250 pg/mL; or left atrial volume index greater than or equal to 34 mL/m2 by transthoracic echocardiography.
The risk of dementia was even stronger when the researchers defined cardiopathy by at least two biomarkers instead of one (aHR, 1.54 [95% CI, 1.25-1.89]).
The authors point out, however, that this study is observational and cannot make a causal link.
Clifford Kavinsky, MD, PhD, head of the Comprehensive Stroke and Cardiology Clinic at Rush University Medical Center, Chicago, told this news organization that much more research would need to be done to show convincingly that atrial cardiopathy causes dementia.
He called the findings “provocative in trying to understand in a general sense how cardiac dysfunction leads to dementia.”
“We all know heart failure leads to dementia, but now we see there may be a relationship with just dysfunction of the upper chambers,” he said.
But it still not clear is what is mediating the connection, who is at risk, and how the increased risk can be prevented, he said.
He said he also wonders whether the results eliminated all patients with atrial fibrillation, a point the authors acknowledge as well.
Researchers list in the limitations that “asymptomatic AFib or silent cerebral infarction may have been missed by the ARIC adjudication process.”
There is broad understanding that preventing heart disease is important for a wide array of reasons, Dr. Kavinsky noted, and one of the reasons is cognitive deterioration.
He said this study helps identify that “even dysfunction of the upper chambers of the heart contributes to the evolution of dementia.”
The study amplifies the need to shift to prevention with heart disease in general, and more specifically in atrial dysfunction, Dr. Kavinsky said, noting a lot of atrial dysfunction is mediated by underlying hypertension and coronary disease.
Researchers evaluated cognitive decline in all participants with a comprehensive array of neuropsychological tests and interviewed some of the patients.
“A diagnosis of dementia was generated based on testing results by a computer diagnostic algorithm and then decided upon by an expert based on the Diagnostic and Statistical Manual of Mental Disorders and the criteria outlined by the National Institutes of Health and the National Institutes of Health,” they write.
Dr. Johansen reported funding from National Institute of Neurological Disorders and Stroke. Study coauthor disclosures are listed in the paper. Dr. Kavinsky has disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.