Higher resting heart rate (RHR) was linked to significantly greater dementia risk and faster cognitive decline independent of cardiovascular disease in a study of more than 2,000 older adults in Sweden.
People with RHR of 80 bpm or higher had a 55% increased risk of developing dementia compared with people whose RHR was 60-69 bpm (adjusted HR 1.55, 95% CI 1.06-2.27), reported Dr Yume Imahori of the Karolinska Institutet in Stockholm, and co-authors.
The association remained significant after excluding people with prevalent and incident cardiovascular disease. Cognitive function scores fell over time in all RHR groups, but people with RHR of 80 bpm or higher declined more quickly than people with RHR of 60-69 bpm, Imahori and co-authors wrote in Alzheimer’s & Dementia.
Previously, the Atherosclerosis Risk in Communities (ARIC) study showed that an RHR of 80 bpm or more in midlife raised the risk of cognitive decline and incident dementia as people aged.
“Our study showed that this finding was also applicable in RHR measured in late life,” Imahori told MedPage Today. “It further revealed that this association was not due to underlying cardiovascular diseases such as atrial fibrillation and heart failure. The study is important because RHR might be used to identify older people with a potentially high risk of cognitive decline in a wide variety of settings,” she added.
“If cognitive function in patients with elevated RHR is followed carefully and early intervention is made, the onset of dementia might be delayed, which can have a substantial impact on patients’ quality of life,” she said. “If further studies show that this association is causal, reducing RHR might be considered as a target of intervention.”
Imahori and colleagues followed 2,147 older adults (62,1% women) in the Swedish National Aging and Care in Kungsholmen (SNAC-K) population-based study, with a mean baseline age of about 71. All participants were dementia-free at baseline and followed regularly from 2001-2004 until 2013-2016. Cognition and dementia status were assessed at multiple timepoints. Baseline mean Mini Mental State Examination (MMSE) score was 29.0 and was similar across RHR groups.
Mean RHR, obtained from a standard 12-lead ECG at baseline, was 65.7 bpm. Participants in higher RHR groups were older (mean age about 72), less educated, and were more likely to be current smokers, physically inactive, and hypertensive. Prevalence of cardiovascular disease (ischemic heart disease, atrial fibrillation, heart failure, or stroke) at baseline was not significantly different among RHR groups.
Over a median follow-up of 11,4 years, 289 people were diagnosed with dementia. High RHR remained associated with dementia after excluding people with baseline cardiovascular disease and those who developed cardiovascular disease during follow-up.
MMSE scores fell faster for people who had high RHR. Compared with a resting rate of 60-69, RHR of 80 or more was associated with annual declines in MMSE score (adjusted β -0.13, 95% CI -0.21 to -0.04); results were similar after excluding prevalent and incident cardiovascular disease. RHR 70-79 also was linked to accelerated drops in MMSE score (adjusted β -0.10, 95% CI -0.17 to -0.04).
The relationship between elevated RHR and cognition might, in part, reflect pathophysiological pathways independent from vascular risk factors, Imahori and colleagues observed. “Nevertheless, we cannot rule out the possibility that subclinical or undiagnosed cardiovascular diseases may contribute to this association,” they wrote.
“This population-based cohort study suggests higher resting heart rate is associated with increased risk for dementia and faster cognitive decline, further adding to the growing body of research showing the health of the heart and brain are closely connected,” noted Claire Sexton, DPhil, director of scientific programmes and outreach at the Alzheimer’s Association in Chicago, who wasn’t involved with the research.
“However, this study only shows a correlation between resting heart rate and cognition, not causation,” Sexton cautioned. “More research is needed.”
Imahori added that caution is needed when generalising findings to other populations, “because our study included mainly Caucasians who had relatively high socioeconomic status”.
Unmeasured confounders and selective survival bias might also have influenced associations in the SNAC-K cohort, the researchers acknowledged.
Association of resting heart rate with cognitive decline and dementia in older adults: A population-based cohort study
Yume Imahori,Davide L. Vetrano,Xin Xia,Giulia Grande,Petter Ljungman,Laura Fratiglioni,Chengxuan Qiu
Published in Alzheimer’s & Dementia Journal on 3 December 2021
Resting heart rate (RHR) predicts future risk for cardiovascular disease (CVD). However, longitudinal studies investigating the relationship of RHR with cognitive decline are scarce.
This population-based cohort study included 2147 participants (age≥60) in SNAC-K who were free of dementia and regularly followed from 2001–2004 to 2013–2016. RHR was assessed with electrocardiogram. Dementia was diagnosed following the Diagnostic and Statistical Manual of Mental Disorders 4th Revision criteria. Global cognitive function was assessed using Mini-Mental State Examination (MMSE). Data were analysed using Cox and linear mixed-effects models.
RHR≥80 (vs. 60–69) bpm was associated with a multi-adjusted hazard ratio of 1.55 (95% confidence interval 1.06−2.27) for dementia. The association remained significant after excluding participants with prevalent and incident CVDs. Similarly, RHR≥80 bpm was associated with a multi-adjusted β-coefficient of –0.13 (–0.21 to –0.04) for MMSE score.
Higher RHR is associated with increased risk for dementia and faster cognitive decline independent of CVDs in a general population of elderly people.
The global burden of dementia has increased rapidly, with 43,8m people affected in 2016. The number of people living with dementia is expected to reach 131m by 2051, with 68% residing in low- and middle-income countries. Dementia has a devastating impact on the quality of life of older adults, their families, and society at large. Currently, there is no cure, but growing evidence suggests that the onset of dementia could be delayed through managing modifiable risk factors. Evidence has also been accumulating that cardiovascular diseases (CVDs) are associated with the development of dementia, including Alzheimer’s disease, possibly because of common risk factors, atherosclerotic changes of arteries, arterial stiffness, micro-embolism, and cerebral hypoperfusion.
Abundant evidence has consistently shown that an elevated resting heart rate (RHR) predicts future CVD events beyond traditional CVD risk factors. A limited number of studies also show that a high RHR is associated with cognitive decline and dementia in the general population of middle-aged adults and in patients with ischemic stroke. However, this association has not been investigated in the general population of older adults. Besides, whether an increased RHR is independently associated with cognitive decline or the association is merely explained by the underlying CVDs has yet to be explored. This is important because an elevated RHR is associated with a higher risk of several CVDs such as ischemic heart disease (IHD), atrial fibrillation (AF), heart failure (HF), and stroke, and these CVDs are known risk factors for dementia. Therefore, a higher RHR may be linked with dementia only through an indirect pathway of these CVDs, and thus not an independent risk factor for dementia.
The aim of this population-based cohort study was to investigate the association of elevated RHR with incident dementia in a general population of older adults. We hypothesised that an elevated RHR was associated with an increased risk for dementia and global cognitive decline in older adults and that their association could be present independent of cardiovascular risk factors and CVDs. We sought to test our hypotheses by examining the associations of RHR with cognitive decline and dementia among older adults with and without prevalent and incident CVDs.
Elevated resting heart rate was associated with incident dementia in older adults. This association was independent from cardiovascular diseases. Elevated resting heart rate was also associated with accelerated cognitive decline.
We showed that elevated RHR was associated with high hazard for incident dementia after adjusting for vascular risk factors in a general population of older adults. Moreover, we explored the effect of cardiovascular disease (CVD) on this association, showing that the association was independent of prevalent and incident CVDs.
This study showed evidence that RHR is a potential risk factor for dementia. While our findings merit further confirmation in different cohorts, future intervention studies to manage high RHR may result in novel preventive strategies of cognitive ageing.
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