I think it's an interesting question.
I believe in the whole predisposed to ms thing (one of those rare people with it on both sides of family), but don't think lifestyle contributes to the triggers. Some have had very little, some have had a lot of physically intensive jobs and lives.
I think major life stresses (like car accidents, etc.), environmental stuff, and certain viruses are much more likely the culprits. What we think was my first flare was right after the first car accident I was in as a teen.
My bro's autoimmune stuff showed up big time after a major accident he was in too, but suspected it was always there. He has RA and Psoriasis.
so to make a long answer short (too late

) I don't think the labor intensive stuff made the MS worse.