I know there was an interview from probably the past 4 years. A british journalist who had interviewed Ali a few times back in the 60s/70s met back up with him and interviewed him again and asked him the very same question. Ali reasoned that there are plenty of people who were never fighters who developed Parkinson's so he has no regrets about his profession. Which I think sort of makes sense. They aren't 100% sure yet on the link but I'm sure being punched in the head for a living really doesn't help things.
You carry a lot of fury behind that computer, your keyboard seems to handle it. To get rid of it, lose some weight and get laid.