Research Highlights:
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Summary
Background
The contribution of atrial heart disease to dementia risk is uncharacterized. Our objective was to evaluate the association of atrial heart disease with incident dementia and the potential mediation of atrial fibrillation (AF) and stroke.
Methods and Results
We performed a prospective cohort analysis of participants in the ARIC (Atherosclerosis Risk in Communities) study who attended visit 5 (2011-2013). We used Cox regression to determine the association between atrial heart disease and dementia risk. Structural equation modeling methods were used to determine potential mediation by AF and/or stroke.
Atrial heart disease was defined if ≥1 of the following at visit 5: terminal P wave force >5000 mV·ms in ECG lead V1, NT-proBNP (N-terminal pro-brain natriuretic peptide) >250 pg /mL or left atrial volume index ≥34 mL/m2 by transthoracic echocardiography.
We repeated our analysis and required ≥2 markers to define atrial heart disease. The prevalence of atrial heart disease was 34% in the 5078 participants (mean age 75 years, 59% women, 21% black adults), with 763 participants developing dementia.
Atrial heart disease was significantly associated with dementia (adjusted HR, 1.35 [95% CI, 1.16–1.58]), with a strengthening of the effect estimate when ≥2 biomarkers were needed (adjusted HR, 1 .54 [95% CI, 1.25–1.89]).
There was an increased risk of dementia among those with atrial heart disease when excluding those with AF (adjusted HR, 1.31 [95% CI, 1.12–1.55]) or stroke (adjusted HR, 1.28 [95% CI, 1.09–1.52]). The proportion of the effect mediated by AF was 4% (P = 0.005), and 9% was mediated by stroke (P = 0.048).
Conclusions
Atrial heart disease was significantly associated with an increased risk of dementia, with only a small percentage of mediation of the effect by AF or stroke.
Comments
Structural or functional abnormalities within the left atrium of the heart, with or without symptoms, can increase a person’s risk of developing dementia later in life by 35 percent, according to new research published today in the Journal of the American Heart Association . The risk of dementia increased even among those who did not experience atrial fibrillation or stroke, two conditions known to be associated with dementia.
The left atrium is one of the four chambers of the heart and is responsible for receiving blood from the lungs and pumping it into the left ventricle, which then pumps the blood to the rest of the body. An abnormality in the structure or function of the left atrium, known as atrial heart disease , can often serve as a biomarker or predictor of a person’s heart risk. Atrial heart disease is associated with an increased risk of stroke and atrial fibrillation, both of which are linked to an increased risk of dementia.
In a study led by Michelle C. Johansen, M.D., Ph.D., assistant professor of neurology at Johns Hopkins University School of Medicine in Baltimore, the research team aimed to determine the relationship between atrial heart disease and dementia, and if so, whether it is independent of atrial fibrillation and stroke.
The study results highlight the need to better understand the relationship and mechanisms between a state of atrial dysfunction , which may be subclinical (without symptoms), and the newly discovered association with dementia, the researchers noted.
Participants in the current analysis were part of a larger study group of more than 15,000 people originally recruited for the ongoing Atherosclerosis Risk in Communities (ARIC) study, which began in 1987 to investigate heart health in people who They live in four diverse communities in the U.S. Study participants were between 45 and 65 years old at the beginning of the study and came from rural areas of the U.S. (Forsyth County, North Carolina and Washington County, Maryland ) and urban areas: Minneapolis and Jackson, Mississippi. All ARIC participants attended clinical visits every three years, and the resulting research and data, including abstraction from hospital records, ECG tracings, and physician and coroner questionnaires, as well as death certificate data, have led to discoveries and guidelines on atherosclerosis, heart disease, kidney disease, diabetes, stroke, and cognitive impairment.
This analysis uses data and assessments collected during participants’ fifth ARIC clinical visit, between 2011 and 2013 as a baseline, and follows participants through their sixth visit, between 2016 and 2017, and their seventh visit, between 2018 and 2019.
The current analysis included 5078 of the 5952 participants who returned for their fifth clinic visit; 59% were women and 41% were men. The group of 5,078 had an average age of 75 and 21% self-identified as black adults. During their fifth, sixth, and seventh clinic visits, ARIC participants were evaluated for cognitive impairment indicative of dementia.
The researchers assessed cognitive decline in all participants with a battery of comprehensive neuropsychological tests from the National Institute on Aging’s Alzheimer’s Disease Centers Uniform Data Set program, as well as an informant interview in a subset of participants. Informant interviews are a question screening test, such as the eight-item informant interview to differentiate between aging and dementia, that is administered to a spouse, adult child, or close friend of the adult being screened. cognitive impairment.
The neuropsychological test battery consists of brief measures of processing speed, episodic memory, language, attention, and executive function. A diagnosis of dementia was generated based on the results of tests performed by a computer diagnostic algorithm and then decided by an expert based on the Diagnostic and Statistical Manual of Mental Disorders and the criteria described by the National Institutes of Health and the National Institutes of Health.
Hospital discharge codes, obtained as part of the ARIC study, either directly from hospital discharge indices or from an indexing service, and death certificate data, obtained as part of the ARIC study of the Automated Classification of Medical Entities system, were also included to evaluate the cognitive status of the participants. Additionally, a cardiac evaluation, including echocardiography, electrocardiography (EKG/ECG), and blood tests, was performed to evaluate the size and function of the left atrium of the heart for signs of atrial heart disease.
Analysis of collective health data found that over more than 30 years of follow-up, 763 people developed dementia and 1,709 developed atrial heart disease. Participants with atrial heart disease appeared to be 35% more likely to develop dementia . When researchers adjusted for participants who experienced atrial fibrillation and stroke , even after accounting for other vascular risks, they still saw a respective 31% and 28% increase in the risk of dementia in patients with atrial heart disease. The researchers suggested that a state of atrial heart disease leading to dementia is not the result of atrial fibrillation or stroke alone.
While the researchers note that the results do not imply causality , they emphasize the importance of reducing the risks of vascular and heart disease. Among the limitations of the study was the possibility that some study participants may have missed asymptomatic atrial fibrillation or silent strokes. Additionally, dementia develops slowly, so some participants with milder symptoms may have been missed and some study patients may have died before dementia was observed and documented. The study also may not be generalizable across populations with demographic characteristics other than the four communities in Forsyth County, North Carolina; Washington County, Maryland; Minneapolis; and Jackson, Mississippi that comprise ARIC.
Clinical Perspective What’s new? Among community-dwelling older adults, atrial heart disease was associated with an increased risk of dementia, even after controlling for known vascular risk, and this association was minimally mediated by atrial fibrillation or stroke. What are the clinical implications? Our findings suggest that abnormalities in left atrial structure or function may be an independent risk factor for incident dementia. |
Co-authors are Wendy Wang, MPH; Michael Zhang, M.D., Ph.D.; David S. Knopman, MD; Chiadi Ndumele, M.D., Ph.D.; Thomas H. Mosley Ph.D.; Elizabeth Selvin, M.P.H., Ph.D.; Amil M. Shah, MD, MPH; Scott D. Solomon MD; Rebecca F. Gottesman, M.D., Ph.D.; and Lin Yee Chen, MD, MS The study was funded by the National Heart, Lung, and Blood Institute of the National Institutes of Health.
