Structural or functional abnormalities within the heart’s left atrium, 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, an open-access, peer-to-peer study. -reviewed 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 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, which are linked to an increased risk of dementia. In a study led by Michelle C. Johansen, MD, 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. , if 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 can be subclinical (showing no 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 to the ongoing Atherosclerosis Risk in Communities (ARIC) study, which began in 1987 to investigate heart health in people living within four diverse communities across the US ARIC. Study participants were between 45 and 65 years of age at the start of the study and came from rural areas of the US (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 the abstraction of hospital records, ECG tracings and questionnaires from doctors and coroners, as well as data from certificates of death, have led to discoveries and guidelines about atherosclerosis, heart disease, kidney disease, diabetes, stroke and cognitive impairment. This analysis uses data and assessments collected during participants’ fifth ARIC clinic 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 5,078 of the 5,952 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% identified as black adults. During their fifth, sixth, and seventh clinical visits, ARIC participants were assessed for cognitive impairment suggestive of dementia.
The researchers assessed cognitive decline in all participants with a comprehensive neuropsychological test battery from the National Institute on Aging’s Uniform Data Set of the Alzheimer’s Disease Centers program, as well as interviewing informants in a subset of participants. Informant interviews are a question-selection test, such as the eight-item informant interview to differentiate between aging and dementia, which is administered to a spouse, adult child, or close friend of the adult who is ‘assess for 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 from the test results of a computerized diagnostic algorithm and then decided by an expert based on the Diagnostic and Statistical Manual of Mental Disorders and criteria outlined 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 or from an indexing service – and certificate data of death, obtained as part of the ARIC study of the Automated Classification of Medical Entities system, were also included to assess the cognitive status of the participants. In addition, a cardiac evaluation, including echocardiography, electrocardiography (EKG/ECG), and blood work, was performed to assess the size and function of the left atrium of the heart to check for signs of atrial heart disease.
The analysis of the Collective Health data found that over more than 30 years of follow-up, 763 people developed dementia and 1,709 had atrial heart disease. Participants with atrial heart disease appeared to be 35% more likely to develop dementia. When the researchers adjusted for participants who experienced atrial fibrillation and stroke, even after accounting for other vascular risks, they still saw a 31% and 28% increase in the risk of dementia in patients, respectively. with atrial heart disease. The researchers suggested that an atrial heart condition that leads to dementia is not just the result of atrial fibrillation or stroke.
Although the researchers note that the results do not imply causation, they emphasize the importance of reducing the risks of vascular and heart disease. Limitations of the study included the possibility that asymptomatic atrial fibrillation or silent strokes may have been missed in some study participants. Also, 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 to populations with different demographics than the four communities in Forsyth County, North Carolina; Washington County, Maryland; Minneapolis; and Jackson, Mississippi, which form ARIC.
Source:
American Heart Association
Journal reference:
Johansen, MC, et al. (2022) Risk of dementia associated with atrial heart disease: the ARIC study. Journal of the American Heart Association. doi.org/10.1161/JAHA.121.025646.