There are quite a few studies that have suggested that surprising factor can influence a person’s risk of multiple sclerosis.
Viruses. Some studies have suggested that many viruses such as Epstein-Barr (mononucleosis), varicella zoster, and the hepatitis vaccine may be the cause of MS. To date, however, this belief has not been proven.
Estrogen. There is growing evidence suggesting that hormones, including sex hormones, can affect and be affected by the immune system. For example, both estrogen and progesterone, two important female sex hormones, may suppress some immune activity.
Testosterone. The primary male hormone may also act as an immune response suppressor. During pregnancy, estrogen and progesterone levels are very high, which may help explain why pregnant women with MS usually have less disease activity. The higher levels of testosterone in men may partially account for the fact that women with MS outnumber men with MS by 2-3 to 1.
