There are many things we can do to try to reduce our risk of dementia, but the condition usually cannot be prevented.
Health
| Analysis
18 January 2023
Observational studies suggest that challenging our brains, for example through brain teasers, can prevent dementia, but this has not been proven.
Getty Images/izusek
This week, the Alzheimer’s Research UK charity launched a campaign to tell people they can reduce their risk of dementia by making certain lifestyle changes, but the impact of such measures is uncertain and probably exaggerated.
The charity’s advice is based in part on a 2020 report from a respected medical journal, The Lancet, which summarized what we know about dementia risk factors. The new campaign, called Think Brain Health Check-in, includes some standard lifestyle advice, such as eating healthy, avoiding smoking and exercising regularly, as well as supposedly dementia-specific measures, such as wearing hearing aids if necessary. and solve puzzles.
The campaign acknowledges that risk factors like our age and genetics cannot be changed, but says that we can modify our diet and how we challenge our brains.
The online tool has changed since it went live on January 18. The initial version, which was used so much that the website struggled to keep up with demand, failed to mention that part of our propensity for dementia is due to lifestyle: “up to 40 percent,” according to the 2020 estimate. The rest of our risk comes down to which versions we have of many genes, which are obviously immutable. This was sent to Alzheimer’s Research UK and they later changed the website to include the 40 per cent figure.
The campaign website also glosses over the fact that all of the risk factors it highlights have emerged from observational research, not higher-quality randomized trials, the best kind of medical evidence. Observational studies can only show correlations between a lifestyle factor and a medical condition, they cannot discover whether the former causes the latter.
These studies are prone to being misleading because a third factor may be behind both the lifestyle habit and the medical condition. In the case of dementia, that third factor may be income, for example. Dementia is more common in low-income people, who also tend to have unhealthy lifestyles in a myriad of ways. This could be the real explanation why some of the stated risk factors, such as eating a certain diet, are correlated with dementia.
Another possible explanation is that people with early cognitive decline may be less willing to carry out some of the healthy habits, such as exercising, socializing or using hearing aids.
This is not to say that the 12 stated risk factors are invalid. Lifestyle likely plays a role in dementia, because although the number of people with the condition is increasing as we live longer, our individual risk of developing the condition at any particular age has decreased. Our genes have not been altered, so this drop must be due to a change in habits.
A spokesperson for Alzheimer’s Research UK says several public health bodies have recommended some of the 12 tips to reduce our risk of dementia, such as avoiding smoking and eating a healthy diet, including in a 2015 report from NICE, the medical guidelines agency. of England and Wales. .
But it seems unlikely that all 12 tips are equally relevant. We have not yet been able to figure out which of the many lifestyle factors should take credit for the ongoing decline in individual dementia risk.
They are probably the ones that also promote heart and blood vessel health, such as avoiding smoking and exercising. This is because there are several different types of dementia, and the type that is caused by damaged blood vessels in the brain, vascular dementia, has had the lion’s share of the drop in risk. The risk of developing the most common form of dementia, Alzheimer’s disease, has not decreased as much.
Of these blood vessel-related risk factors, having high blood pressure seems particularly likely to genuinely contribute to dementia, according to a 2021 study that used “Mendelian randomization,” a relatively new way of investigating medical conditions that uses variation Random genetics to mimic randomized trials.
That same study also suggests that high cholesterol levels and high blood sugar levels do not contribute to dementia and may be correlated with increased risk. Despite this, Alzheimer’s Research UK’s new campaign includes recommendations for keeping cholesterol levels in check and suggests that high blood sugar levels could also be a risk.
Another questionable orientation in the campaign is that there is no safe level of alcohol consumption, when observational studies show that light consumption is correlated with a lower risk of dementia.
The 12 tips are described as “simple rules for better brain health,” as if there’s no doubt about the effectiveness of any of them.
In response, Alzheimer’s Research UK Medical Director Jonathan Schott defended the campaign, saying the public asks the charity for prevention advice and has therefore provided it. “Our Check-in is there to raise awareness and empower people; It is not perfect science and we do not claim that it is,” a spokesperson added.
It’s understandable that people want to do everything they can to avoid dementia, but surely no one wants to be cheated. Sometimes the honest answer to a scientific question should be, “We don’t know.”
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Source: news.google.com