The odds of developing MS are only 1 in 750, but the odds increase to just 1 in 40, if a relative has MS. Further genetic evidence is indicated by the fact that the chances of MS increase tenfold if an identical twin has MS, to 1 in 4.
Vitamin D Link
The Graph Below: illustrates the prevalence of MS around the world. Nations with darker red shades have higher rates of MS than lighter yellow nations. This depicts the the trend that MS may be tied to Vitamin D deficiencies in areas further from the equator with less regular sunlight. The prevelenc of MS increase substantially for individuals who live above or below 40 degrees latitude.
Prevalence
Nearly 350,000 cases in the US alone
MS is more common in females than males by 2 to 1.