In this interview, we speak to Dr. Yume Imahori about her latest research which looks at whether heart rate could be used as an early risk factor for dementia.
Please could you introduce yourself and tell us what inspired your latest research into dementia?
My name is Yume Imahori, a postdoctoral researcher working at the Aging Research Center, Karolinska Institutet in Stockholm, Sweden. I was originally a physician in Japan and obtained a Master’s degree in Public Health and a Ph.D. degree in Epidemiology from the London School of Hygiene & Tropical Medicine. Now I work as an epidemiologist. My main research interest focuses on cardiovascular health and brain aging.
The burden of dementia has been increasing worldwide, especially in low- and middle-income countries. This is a huge problem because access to the hospital, good diagnosis, and good management can be difficult in these countries. To delay the onset of dementia, it is important to have an affordable and accessible way to find people with high dementia risk and intervene earlier. Resting heart rate is simple, easily measured, and inexpensive. I was interested in whether this simple marker was associated with brain aging disorders like dementia, and this motivated me to carry out this research.
Dementia is continuing to increase globally and is expected to reach 139 million by 2050, yet there is still no cure. Why is this and why is it, therefore, critical to keep researching risk factors for dementia that could lead to earlier intervention?
Unfortunately, it is very difficult to find effective drugs to cure dementia. Dementia is a very complicated health condition, and we are still not 100% sure about its underlying biological mechanisms. Besides, not many drugs can reach the brain because the brain is protected by a barrier. As a result, many potential dementia drugs have shown disappointing effects.
However, the good news is that we know much more about risk factors for dementia now, which we can modify. For example, a very rigorous study showed that good control of high blood pressure could slow down cognitive decline. So it is extremely important to find risk factors for dementia so that we can take actions to delay it.
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Can you describe how you carried out your latest research into dementia? What did you discover?
We followed 2147 dementia-free elderly people in Stockholm for 12 years and regularly assessed their dementia status and cognitive function. We found that elderly people with a faster heart rate (more than 80 beats per minute) at the beginning were more likely to experience faster cognitive decline and dementia compared to people with a slower heart rate (60-69 beats per minute).
We thought that the reason might be because people with faster heart rates have heart diseases and are unhealthier. But even after we excluded people with heart diseases, a faster heart rate was still associated with a high risk for dementia and cognitive decline.
Were there any limitations to your research? If so, what were they?
Our study is an observational study, which means that our study cannot give clear evidence of a causal relationship between heart rate and risk of dementia. So future research is necessary to confirm our research. Besides, the people in our study were mainly white and relatively well-off. So what we found in our study might not be applicable for people with different backgrounds and ethnicity.
What further research needs to be carried out to further validate your initial findings?
There are only a couple of good studies showing the association between faster heart rate and dementia. We will be more confident if our findings can be replicated among different populations in the future.
Ideally, an experimental study, which is called a randomized controlled trial, will be able to show whether a decrease of fast heart rate through medication or exercise slows down cognitive decline and reduces the risk of dementia, then we will feel confident to conclude whether heart rate might be a target of intervention to prevent dementia.
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As heart rate is easily measured, do you hope that this will help to identify more people that are at risk of developing dementia leading to earlier intervention?
I think that heart rate can be a simple marker for doctors and patients to think about brain health and pay more attention to their heart rate and risk of brain aging. I think that awareness is very important. Recently more people are aware of the risk factors for heart attacks and pay more attention to their heart health. This has helped prevent many heart attacks in high-income countries.
On the other hand, I feel that people pay less attention to healthy brain aging. According to the medical journal Lancet, if 12 dementia risk factors are modified, 40% of dementia can be delayed. So if both physicians and patients are careful about brain aging, we can do more to delay dementia, which matters a lot to people’s quality of life.
How will early intervention of dementia impact a patient's quality of life?
Dementia is a major cause of disability and institutionalization in older people, which leads to poor quality of life. Recent studies suggest that prevention measures to adopt healthy lifestyles, manage vascular risk factors, and engage mental and social activities may help maintain good brain function and delay dementia onset. This may help achieve living a longer, healthier life.
What does the future of dementia research look like to you?
Many modifiable risk factors for dementia have been identified. Now it would be important to know to what extent we can reduce the risk or delay the onset of dementia by interventions targeting multiple modifying risk factors in a rigorous experimental study. If we could demonstrate the effectiveness, we can implement a good strategy to prevent dementia.
What are the next steps for your research?
Heart attacks are the number one killer worldwide. But the treatment has improved dramatically, and many elderly people live with a heart attack history now. We plan to research to see the effect of heart attacks on brain aging and dementia.
Where can readers find more information?
You may find the research article from the web at https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.12495. You may more information about the SNAC-K project on which this study is based from https://www.snac-k.se/.
About Dr. Yume Imahori
Yume Imahori is a medical doctor from Japan. She is currently a postdoctoral researcher at the Aging Research Center. Her research focuses on the topic of cardiovascular disease and cognitive aging outcomes using the Swedish National Study on Aging and Care in Kungsholmen population study (SNAC-K)..jpg "Dr. Yume Imahori")
She completed her Ph.D. in Epidemiology in 2019 at the London School of Hygiene & Tropical Medicine. She also holds an MSc degree in Public Health.
About Chengxuan Qiu
Chengxuan Qiu is Associate Professor and Senior Lecturer at Karolinska Institutet in Stockholm, Sweden. He is an epidemiologist. His research has focused on epidemiology of aging and dementia, especially with regard to cardiovascular health, briain aging, and multimodal interventions of dementia.
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