- Dementia affects millions of older people, and researchers expect the number of people with dementia in the United States to nearly triple by 2060.
- There is no known cure for dementia. However, some behavioral changes can reduce the risk.
- A recent study found an association between light intensity exercise and reduced risk of dementia in the elderly.
- Scientists need to do more work to determine whether the association is causal.
In a new study, researchers have identified an association between light-intensity exercise in the elderly and a reduced risk of dementia.
The study, which appears in JAMA open network, sets the stage for further research to determine whether light-intensity exercise causes risk reduction.
According to Centers for Disease Control and Prevention (CDC), dementia is a general term for a number of conditions characterized by cognitive impairment.
Dementia typically affects people over the age of 65, although it is not an expected part of aging. The most common type of dementia is Alzheimer’s disease.
Alzheimer’s disease is a neurodegenerative disease, which means it gets worse over time.
According to World Health Organization (WHO)During the early stages of dementia, someone may become forgetful, lose track of time, or fail to remember a familiar person. In its advanced stages, dementia can significantly reduce an individual’s awareness of the world.
There is no known cure for neurodegenerative dementia. Instead, doctors focus on reducing symptoms and promoting lifestyle changes that could reduce the risk of developing dementia.
In the present study, the researchers investigated whether there was an association between low-intensity exercise and a reduced risk of developing dementia in the elderly.
The study involved 62,286 participants who were 65 or older, had no dementia diagnosis and had medical records in the Korean National Health Insurance Service database.
The researchers collected data between January 2009 and December 2012 and monitored the participants until the end of December 2013. They completed the data analysis from July 2020 to January 2021.
Women represented 60.4% of the participants and the mean age was 73.2.
Participants recorded their physical activity level at the start of the study period using a self-reported questionnaire. The researchers looked at the frequency, intensity and duration of exercise to determine how much energy expenditure was due to physical activity.
After an average follow-up period of 42 months, the researchers noted how many participants developed dementia.
During the follow-up period, 6% of the participants developed dementia.
The researchers divided the participants into four groups according to how active they were: inactive, not active enough, active and very active.
They found that inactive participants had a 10% reduced risk of developing dementia compared to inactive participants.
Active participants had a 20% reduced risk, while highly active participants had a 28% reduced risk.
The results remained the same even after taking into account age, gender and the incidence of stroke and other comorbidities.
Medical news today spoke to Dr. Boyoung Joung, professor of internal medicine at Yonsei University College of Medicine in Seoul, Republic of Korea, and the corresponding author of the study. Said that “[i]In our study, we would like to emphasize that even light intensity physical activity, as opposed to total sedentary behavior, could lead to a reduction in the risk of dementia ”.
“Therefore, seniors who cannot perform activities beyond moderate intensity physical activity, due to […] frailty or comorbidities, could benefit from low intensity physical activity “.
“There are some reports that light intensity physical activity is associated with metabolism and this vascular, cellular and metabolic change due to light intensity physical activity could be helpful in reducing the risk of dementia.”
– Dr. Boyoung
The professor. Paul M. Matthews, Director of the UK Center for Dementia Research at Imperial College London in the UK, explained to MNT that “[t]his is a well-conducted retrospective epidemiological study. The results are consistent with previous similar studies in other populations and with the conclusions of the prospective and randomized FINGER study ”.
“However, as an observational study, it can only be used to suggest that light physical activity can reduce the risk of dementia. [T]the findings cannot be interpreted directly as evidence that starting light physical activity will reduce the risk of dementia, ”warned Prof. Matthews, who was not involved in the study.
MNT he also spoke with prof. John Gallacher, director of Dementias Platform UK, at the University of Oxford in the UK, who was not involved in the study. He agreed with prof. Matthews, explaining that the findings were significant, but the question of causation was crucial.
“The idea that physical activity reduces the risk of dementia is entirely plausible, and these findings add to a growing body of evidence to support this idea. The problem is reverse causation – that people with dementia exercise. Less”.
– Prof. John Gallacher
“This study goes some way to address this problem by examining incident events and eliminating subjects with incident dementia in the first 2 years of follow-up. The dose-response curves are impressive, “he continued.
Prof. Gallacher stated that “[p]possible mechanisms [for the association] they include better vascular health and better immunological function. These mechanisms are likely to be interconnected and not independent of each other. “
The professor. Matthews also believed that some variables that the researchers did not take into account could explain the results. However, biological mechanisms were also possible.
“Among other factors, the study could not control the differences in relative frailty, social integration and family background. A trivial explanation for the results is that these kinds of uncontrolled variables accounted for the differences. “
“Alternatively, there is biological evidence that physical activity could increase levels of factors that protect neurons, improve metabolism to reduce rates of ‘senescence’ – cellular aging – and brain plasticity,” said Prof. Matthews.
Talking with MNT, Prof. Tara Spiers-Jones – Personal Chair of Neurodegeneration and Deputy Director of the Center for Discovery Brain Sciences at the University of Edinburgh, UK – said: “[t]the study of modifiable risk factors for dementia is very important since the best estimates suggest that over a third of cases of dementia can be prevented by modifying the lifestyle ”.
“This study by Yoon and colleagues observes an association between exercise and reduced risk of dementia. Although this type of study cannot prove that exercise is the cause of the reduced risk, the data is solid and comes from a large number of people, ”said Prof. Spiers-Jones, who was not involved in the study.
“This study is important because it suggests that even light exercise can reduce the risk of dementia. This work could be developed by making formal tests of the preventive power of the exercise, some of which are currently underway around the world ”.
Continuing, Prof. Spiers-Jones said MNT that “This study shows that exercise has been associated with the prevention of Alzheimer’s disease more than vascular dementia, which is consistent with previous data. We don’t know why this is the case, but it is possible that other risk factors such as ‘hypertension and diabetes are more influential in vascular disease risk than exercise.’
Dr Boyoung agreed, noting that “[o]Other modifiable risk factors, such as hypertension and diabetes, could play an important role in vascular dementia. That’s why physical activity was more protective against Alzheimer’s disease than against vascular dementia. “
Prof. Gallacher explained that “[t]the absence of effect for vascular dementia is inconsistent with the mechanisms described above. However, the analysis, in checking for variables related to vascular disease – blood pressure, body mass index, etc. – could have corrected effects on vascular dementia. A more detailed analysis would demonstrate this. “
For prof. Matthews, “[t]he genetic basis for [Alzheimer’s disease and vascular dementia] it is distinct and the extent to which genes alone determine them differs. This suggests that modifying specific risk factors should have different effects on the two clinical outcomes ”.
Dr. Boyoung said further research with a longer follow-up analysis and a more detailed overview of participants’ exercise levels would be valuable.
“Since dementia has a long subclinical period, further studies with a relatively longer follow-up duration are needed. Also, as physical activity patterns may change during [the] follow-up period, studies considering this change in physical activity are warranted, ”said Dr Boyoung.
The professor. Gallacher also noted some ways the researchers could develop the study.
“Since dementia has a presymptomatic stage of 10-15 years, the study could be improved by eliminating subjects with incident dementia in the first 5 years of follow-up, but I suspect the study is too small for that.”
“So a larger study is needed. Furthermore, the replies to the questionnaire are subject to errors. A study that uses actigraphy to objectively evaluate physical activity would be an important next step “.
“All these arguments aside, the balance of risk is that exercise is good and a little goes a long way!” concluded prof. Gallacher. The professor. Spiers-Jones agreed:
“The take-home message from this and similar research is that it is important to exercise to protect the brain as we age.”