What if heart disease saves me from dementia? I'm not just being contrarian. I think about this a lot of the time. I'm already 40. I'm being healthy now, but whatever damage has already been done is baked in. (plus whatever is in my genetics) A quick death at 65-70 might be much more preferable to a slow terrible decade-long decline.
New medical discoveries happen regularly; you might also die right before the discovery of a preventative/cure for dementia. Living people have options, dead people have none.
Also, given the preferences you expressed in your comment, you especially should want to avoid strokes, or the many side effects of heart disease, which can make you less healthy for a long time.
Heart disease can be a slow decade long death, where you become incapable of physically doing anything. It's not just a heart attack out of nowhere and you're dead.
My grandfather always said "there's something to be said for a good coronary." He was in his 70's when he said it, and his point was that he had a good run, and there's an argument for going out while things are still good rather than slowly dying over six months in a nursing home (which is what actually happened).
