A risk factor raises your chance of getting a health problem.

You can get MS with or without the risk factors below. But the more risk factors you have, the greater your chances of getting it. If you have many, ask your doctor what you can do to lower your risk.

Risk factors are:

Medical Problems

A viral infection may trigger MS. Researchers have been looking into a type of herpes virus, human herpes virus-6, and Epstein-Barr virus. Some believe that it is the way some people respond to the virus that may trigger MS.

People who have had optic neuritis (swelling of the optic nerve) have a high risk.


People between 16 and 40 are at higher risk. This is when MS is found in most people.


MS is found in women at younger ages than men. MS is found in men and women at equal rates later in life.


MS may be due to your genes because it happens in families. Researchers think more than one gene is to blame.

People with a family history of problems with their immune system, such as systemic lupus erythematosus, are also at greater risk.

Ethnic Background

MS is more common in people of European descent.

Vitamin D

Some studies have found that people with lowvitamin D levels had a greater risk of MS. But researchers are still looking into this.

If you are worried about your vitamin D level, talk to your doctor. Your blood can be tested. Vitamin D can be found in foods like cod liver oil, salmon, mackerel, sardines, and milk that contains it. You can also get it from the sun. It triggers your body to make it.

Other Factors

Smokingis thought to be linked to a higher risk.


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11/9/2015 DynaMed Plus Systematic Literature Surveillancehttp://www.dynamed.com/topics/dmp~AN~T116285/Multiple-sclerosis-MS: Kuo CF, Grainge MJ, Valdes AM, et al. Familial aggregation of systemic lupus erythematosus and coaggregation of autoimmune diseases in affected families. JAMA Intern Med. 2015;175(9):1518-1526.

Last reviewed September 2018 by EBSCO Medical Review Board Rimas Lukas, MD  Last Updated 9/26/2018