Dementia is not inevitable. That is the key conclusion of a review of the best available evidence on dementia, recently published in The Lancet. In fact, a full 1 out of every 3 dementia cases may be preventable by making the right lifestyle choices.
The study’s focus was on the top known modifiable risk factors. If these risk factors are reduced or eliminated with lifestyle changes, so is your chance of cognitive decline, and eventual dementia in the form of diseases like Alzheimer’s.
Here is a diagram from the paper showing the risk factors, and how much each one has been found to reduce dementia over a lifetime:
The factors include hearing loss, education, smoking, depression, physical inactivity, social isolation, hypertension, obesity, and diabetes.
The researchers also looked at what steps you can actually take to reduce these risk factors, and how they affect brain damage, brain inflammation, and cognitive reserve—three mechanisms believed to be responsible for dementia.
Some of the steps are obvious (miraculously, to eliminate the smoking risk factor, all you have to do is stop smoking), but others not so much. Preserving your hearing has a surprisingly large effect. Cognitively stimulating activities, such as reading, puzzles, and crosswords—but importantly, not commercial brain training—have shown promise, especially combined with other interventions. And perhaps obvious, but still worth pointing out, is that exercise is a big one. It has been found to attack the risk of dementia from all three angles by reducing brain damage, reducing brain inflammation, and increasing cognitive reserve.
Does that mean everyone should focus on getting more exercise?
Not necessarily—one of the key messages outlined in the paper is that dementia care should be tailored to unique individuals. This is where tracking comes in. By keeping tabs on your own cognitive health, alongside your own lifestyle changes, you’ll have the data you need to apply some of these scientific recommendations in your own life. If you have real evidence that exercise is making a difference in your life, it’s not only easier to stay motivated, but you have something more than subjective feelings to discuss with a healthcare professional when developing a plan for preventing dementia. Tracking is the key to changing.
UPDATE: This article was originally published in 2017, but since then, the Lancet Commission has updated their data and modelling to incorporate three new risk factors for dementia, based on the latest evidence from 2020. The new risk factors are: excessive alcohol consumption, traumatic brain injury, and air pollution. With 12 modifiable risk factors now identified, we know that about 40% (up from 35%) of worldwide dementias can theoretically be prevented or delayed.
The new report also addresses the COVID-19 pandemic, noting that people with dementia make up a disproportionate number of deaths from the disease. It's all the more reason to take action to prevent dementia, at a policy level, an individual level, and through the healthcare system. The new report gives us even more reason for hope, identifying new areas to tackle, and greater reassurance that a few changes can make a big difference.