I have rarely seen a person of color with a neurodegenerative disease. Most of the people with dementias and Alzheimer's are white women in my experience. I have only seen one black (woman) person with ALS; I've seen one white woman with ALS--all the rest have been men, but I admit I'm seeing more ALS patients nowadays. I mostly see Parkinson's in men, but a few women too. Parkinson's and ALS seem to be on the rise. Most of these are farmers and veterans. I haven't noticed a similar rise in Alzheimer's. Of course, this is all anecdotal and means little in the larger context.
But these trends are why we have to have a written plan, instructions for our families to carry out our wishes. Most people are never even informed they have dementia. Just talking about it makes people feel uncomfortable and slightly embarrassed. But after stage 4 of Alzheimer's dementia, you're no longer considered safe to live alone or make decisions. It's very important you make decisions before you reach that point and write them down so others can carry them out on your behalf.
The increase in neurological disease is one more of the great tragedies of our time.