got curious, googled it, here’s something interesting:

https://news.usask.ca/articles/research/2018/u-of-s-study-hones-in-on-causes-of-ms-disability.php

seems genetic. which makes sense.

apparently that region just got unlucky with its gene pool, though, as the news release states: more research is necessary in order to be certain.

being caused by environmental chemicals hasn’t been definitively ruled out, but it’s not looking likely

(btw, bravo on an actually readable press release by a university!)