Let's get this out of the way: There are some things that increase your risk of dementia that you won't be able to do anything about.
And then there are risk factors from your environment and lifestyle that you could do something about.
That's what we're going to focus on here, because those are the factors that are reported (and misreported) the most.
With help from the Alzheimer's Society, we've looked at how strong the evidence is for each risk factor. Here's what you need to do to lower your risk, and what you don't need to worry about.
1. DO: Get some exercise.
2. DO: Quit smoking.
This is probably because smoking is related to cardiovascular disease and high blood pressure, which could cause damage to blood vessels in your brain.
If you're a smoker right now, I have good news: There's some evidence that if you quit smoking your dementia risk will go back to that of a nonsmoker.
Verdict: Strong evidence that smokers are more likely to get dementia.
3. DO: Protect your head.
4. DO: Eat a healthy diet.
5. DO: Try to get enough sleep.
6. MAYBE: Do a crossword.
7. DON'T WORRY ABOUT: Eating specific foods or taking supplements.
8. DON'T WORRY ABOUT: Watching too much TV.
9. DON'T WORRY ABOUT: Playing video games.
You might have seen media reports of video gaming being linked to Alzheimer's. This was based on a paper published in the journal Proceedings of the Royal Society B that found people who play a lot of video games make increased use of a certain part of the brain that has previously been linked to a decrease in the volume of the hippocampus. Other studies have suggested that a reduced hippocampus volume can mean an increased risk of Alzheimer's... Still with us?
The original paper did not look at hippocampus volume, and did not mention Alzheimer's once (though, unsurprisingly, the press release for the study did).
As Professor Chris Chambers and Dr. Peter Etchells wrote in The Guardian, this series of logical leaps can't be equated to evidence that video games increase your risk of Alzheimer's.
There have been other studies looking at whether playing certain kinds of video games might actually improve cognition in older people. One randomised control trial published in the journal Frontiers in Aging Neuroscience suggests that non-action video games might help improve some aspects of cognition, but there is no evidence that this translates to reduced rates of dementia.
Verdict: No evidence that video games increase your risk of dementia.