by EBSCO Medical Review Board

A risk factor is something that raises the chances of getting a health problem. A person can get MS with or without the ones listed below. The chances of getting MS are greater in people who have many risk factors.

MS is more common in people between the ages of 16 and 40. This is when MS is most often found. It is also more common in people of European descent.

Other things that may raise the risk are:

Health Problems

A viral infection may trigger MS. Researchers have been looking into 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 (inflammation of the optic nerve) have a high risk.


MS may be due to genes that may run in some 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.

Vitamin D

Some studies have found that people with low vitamin D levels had a greater risk of MS. This is an active area of research.

People who are worried about their vitamin D levels should talk with their doctors. Vitamin D levels can be checked with a blood test. Vitamin D is found in foods like cod liver oil, salmon, mackerel, sardines, and milk that contains it. A person can also get it from the sun. It triggers the body to make it.

Other Factors

Smoking is thought to be linked to a higher risk.


Multiple sclerosis (MS). EBSCO DynaMed website. Available at: Accessed March 16, 2022.

NINDS multiple sclerosis information page. National Institute of Neurological Disorders and Stroke website. Available at: Accessed March 16, 2022.

What is MS? National Multiple Sclerosis Society website. Available at: Accessed March 16, 2022.

Revision Information

  • Reviewer: EBSCO Medical Review Board Rimas Lukas, MD
  • Review Date: 11/2021
  • Update Date: 03/16/2022