I find this report on the increase in MS in Iran to be quite interesting - particularly when considered with the perinatal vitamin D hypothesis (that perhaps a vitamin D deficiency in the first 5 weeks of fetal development leads to abnormal... vascular development).
I looked back into Iranian history ...what happened about 30 years ago (cause the people who are being diagnosed now are around 30).
Guess what? The Islamic Revolution happened.
Women (expectant mothers and all) suddenly conformed with a traditional dress code, which involved covering up most skin. Could this social phenomena be adding to vitamin D deficiency (which is considered a risk factor to being predisposed to MS and MS relapses).
Similarly, in Australia...there has been increased use of sunscreen, creating an invisible cloak. Vitamin D deficiency is common in Australia, even in Southern Queensland - which gets plenty of sunlight. Social behaviour effectively leading to an increased risk of developing a vascular abnormality?
I'm not saying to avoid traditional dress, or sunscreen. Vitamin D can be obtained from sunlight to the skin, certain foods (shitake mushrooms and atlantic salmon have high quantities), or from a vitamin supplement.