January 2023 Research Wrap
Welcome to our January Research Wrap about risk factors for dementia. We are excited to be restarting our monthly research blogs. Please get in touch if you have information, you would like included in our next Research Wrap.
The number of people with dementia worldwide is increasing due to population ageing. The number of people with dementia is expected reach 153 million by 2050 worldwide, compared with an estimated 57 million cases in 2019, according to projections published in a The Lancet Public Health article, “Estimation of the Global Prevalence of Dementia in 2019 and Forecasted Prevalence in 2050: An Analysis for the Global Burden of Disease Study 2019.”
Dementia will continue to be among the leading causes of death and disease worldwide, unless effective treatments are found, and nations begin to address some of the common risk factors for dementia, including obesity, diabetes, misuse of alcohol and other drugs, including smoking.
It has been estimated that around 40% of all dementia cases may be the result of modifiable risk factors:
High blood pressure, and other cardiovascular risk factors.
Smoking cigarettes, including vaping.
Diabetes.
Obesity.
Lack of physical activity.
Poor diet.
High alcohol consumption.
Drinking large amounts of alcohol is known to cause brain changes.
Low levels of cognitive engagement.
Head trauma including Traumatic Brain Injury.
Depression.
Social isolation.
Low levels of engagement.
Air pollution.
We also acknowledge that some people will get dementia despite having lived healthy lives and avoiding these risk factors.
Below we provide several studies with some commonly known risk factors, and less known risk factors for dementia. Our Strategic Partner Dementia Australia also has an excellent summary on the risk factors for dementia, and information about lowering your risk of dementia, as do other websites on dementia.
Dementia Risk and Hearing: The Lancet Commission’s 2020 report suggests that hearing may be especially important to study in terms of dementia risk.
Although research has shown an association between age-related hearing loss and the risk of dementia, it is still unclear as to what drives this association. Some of the possibilities which have been considered include:
· Hearing loss can cause social isolation/depression which may be linked to increase risk of dementia
· Hearing loss could cause changes in how the brain processes information and more resources are being put towards trying to hear which takes away from other areas of functioning
· Reduced exposure to auditory stimuli could lead to changes to the brain
· Changes to the brain associated with Alzheimer’s disease or other dementias may lead to changes to central auditory processing (before the dementia has been diagnosed).
A study published Oct. 13 in JAMA Otolaryngology suggests that central auditory processing – or how the brain processes sound – could provide further insight.
In an observational study of 280 older adults without dementia, researchers found that people who performed at intermediate and poor levels on dichotic tests (were at substantially increased risk of developing dementia. In a standard dichotic listening test, a participant is presented with two different auditory stimuli simultaneously (usually speech), directed into different ears over headphones. This test is used to measure aspects of central auditory processing.
"The outcome of our publication is a step in the right direction to better understanding risks for Alzheimer's disease and improving our ability to detect early signs of neurodegenerative disease," said lead author Adeeb Mohammed, a UW undergraduate in neuroscience and biochemistry.
Co-senior author Paul Crane, professor of medicine at the University of Washington School of Medicine and principal investigator of the Adult Changes in Thought research program at the UW, said this study suggests that further research on the relationship between hearing and dementia risk should consider adding dichotic tests as part of the measurement, and that “Hearing is more complicated than you think.”
So do not put off that hearing test, and if prescribed, wear your hearing aid!
Exercise and Dementia Risk: Being physically active is one of the best ways to reduce risk factors for cognitive decline and dementia. Being physically active helps to ensure your brain is getting a good supply of oxygen and helps to reduce the risk of other conditions including depression, diabetes and heart disease which are associated with an increased risk of dementia.
A recent study published in the journal Neurology, looked at the association between physical and mental activity and the risk of developing dementia. More than 500,000 people who did not have dementia were recruited to participate in this study. Participants completed surveys about their physical and mental activity. Their susceptibility to dementia, based on family history, was also recorded. They were then followed for approximately 11 years. During that time, 5,185 people involved in the study went on to develop dementia. The risk of developing dementia was decreased for people who regularly participated in vigorous activities like exercise and sports. Even doing regular household chores and having family visitors reduced the risk.
Some exercises to consider adding to your routine, according to Jonhenry and Silky Singh Pahlajani, a clinical professor of behavioral neurology and neuropsychiatry at Weill Cornell Medicine include:
1. Walking or power walking
2. Riding a bicycle or exercise bike
3. Swimming
4. Running
5. Cardio machines such as the elliptical (cross trainer)
6. Circuit training
People with dementia will also benefit from staying physically active. They may benefit from a personal trainer or exercise physiologist to support them to maintain an exercise program, or even to remember how to do them
Obesity, Diabetes and Dementia: Obesity increases your risk of diabetes, and together, obesity and diabetes increase your risk of dementia. In The Role of Obesity and Diabetes in Dementia, the authors state “Obesity is often the cornerstone that leads to the development of diabetes and, subsequently, in the case of type 2 diabetes mellitus (T2DM), progression to “type 3 diabetes mellitus (T3DM)”. Obesity and depression are closely associated with diabetes.”
Decades of research also tells us obesity increases the risk of getting cancer. Clearly, it is important to have a healthy diet and maintain a healthy weight to promote good physical and brain health.
Dementia timely diagnosis: A timely diagnosis of dementia is essential to support people to access early intervention, appropriate care plans, and to manage symptoms appropriately. Many people who experience delays in diagnosis experience significant distress as they try to understand the cause of their symptoms. A recent research report explored who was more likely to have access to a timely diagnosis of dementia or mild cognitive impairment.
In an observational study published in the Journal of General Internal Medicine Oct. 13, researchers in the United States looked at 4,760 participants with dementia and 1,864 participants with mild cognitive impairment. They found that only 26% of people with dementia and just 11.4% of people with mild cognitive impairment received a timely diagnosis.
Non-Hispanic Black respondents and respondents with less than a college degree were significantly less likely to receive a timely diagnosis than non-Hispanic white respondents with a college degree. Respondents who lived alone were also less likely to receive a timely diagnosis of dementia, though not mild cognitive impairment. Diagnosis of both conditions increased over time.
Researchers concluded that targeting resources for timely diagnosis of cognitive impairment to individuals from racial and ethnic minorities or lower educational attainment, and those living alone, may improve detection and reduce disparities in obtaining timely diagnosis of dementia and mild cognitive impairment.
Everyone also has a human right to an accurate and timely diagnosis.
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