I wonder if the issue could be neurotransmitter disruption, like dopamine. Or, could it be damage to a part of the brain that regulates body functions. I think if it were only traumatic injury, then we would not see the vast differences in MS rates. Do people in Canada have higher brain injuries than people in the Bahamas? I've never had brain injury, but was in a non-injury car accident a few weeks before my first symptom.