Higher resting heart rate (RHR) was linked to 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 Yume Imahori, MD, PhD, 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."
"This 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," Imahori 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 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 followup 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 followup.
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 programs 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 generalizing 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.
-
Judy George
covers neurology and neuroscience news for MedPage Today, writing about
brain aging, Alzheimer’s, dementia, MS, rare diseases, epilepsy,
autism, headache, stroke, Parkinson’s, ALS, concussion, CTE, sleep,
pain, and more. Follow
Disclosures
SNAC-K is supported
by the Swedish Ministry of Health and Social Affairs and the
participating county councils and municipalities, along with additional
grants from the Swedish Research Council and the Swedish Research
Council for Health, Working Life and Welfare.
Imahori had no
disclosures. Other researchers reported relationships with
AFA-Insurance, Carl Bennet AB, FORMAS, FORTEO, Strategic Research Area
Epidemiology Karolinska Institute, and the International Society for
Environmental Epidemiology.
