http://journals.sagepub.com/doi/full/10 ... 8511421105
a few possibilities missing from this proposal, to my way of thinking anywayProposal
It is clear that multiple sclerosis (MS) has a complex aetiology that involves both genetic and environmental factors and that both make a significant contribution to causation. However, the weight of evidence would favour a significantly greater role for the environment over genetics. There is now ample evidence for a profound effect of the environment on MS causality, with at least four and probably more factors directly contributing, with the reported effect sizes significantly greater than any identified genetic factor....
- latitude, sunlight exposure (UVR), and vitamin D (odds ratio [OR] ≈ 20);1
prior Epstein–Barr Virus (EBV) infection timing and adaptive immune response to EBV (OR = 12.5);2
cigarette smoking (OR = 1.4);2
the hygiene hypothesis (OR ≈ 3).3
Conclusions
The weight of evidence would support the assertion that the environment is more important than genetics in the causation of MS. Environmental factors may provide >75% of the risk of developing MS. Although genetic factors are important and may play a significant role in the development of MS in individuals not exposed to the discussed environmental factors, they are by no means the major driver of MS causation in the vast majority of MS cases.