I've had chronic insomnia my entire life, and when I do sleep, it is never deep sleep, to the point that I typically retain enough brain activity to lucid dream.
Dementia isn't an if for me, it's a when. I also think that they have the causation backwards.
The root causes that lead to my lifelong chronic insomnia are likely the same root causes that will lead to dementia. Genetics, environment. And that says nothing of my ADHD and physical disability which lead to not exercising enough and phases of poor dietary choices, it all swirls into a high risk factor for dementia.
It does seem to be like 90% about being privileged enough to spend a lot of time outside in the sun, running around with people in a group. Maybe in the distant future we will revert to this kind of hunter gater life just because this one kinda sucks.
I feel you. In addition, I'm on a nightly hypnotic. Both the insomnia and the marginally effective drugs are implicated in dementia and I'm beginning to make my peace with it. Medicine has no answers and doctors don't usually take it very seriously.
I have a plan when it starts to show up, or if the strings of terrible days get to be just a little too long.
Dementia is one thing but a string of terrible days is worth holding out till the end. If you're having trouble making the equation work for you, my advice is to devote yourself to alleviating the pain of others. Works for me anyway. Hopefully it's a universal approach.
Maybe I'll get lucky! I certainly believe that one's outlook can have huge impact on their overall health, and that focusing on such things might just make it a self-fulfilling prophecy. For now, I seem to check off a majority of the risk factors. Focusing on diet and exercise and just taking things one year at a time.
Dementia isn't an if for me, it's a when. I also think that they have the causation backwards.