What Causes Multiple Sclerosis?
Since it isn’t known exactly what causes MS, physicians can’t foresee?with certainty who will develop the disease, but they do know there are some things that may put you at higher risk.
Genetic Differences Are a Contributing Cause
And even people with certain predisposing genetic variants may never get MS. In the general population, the risk of developing MS is about 1 in 750 to 1,000. Ariele Greenfield, MD, a neurologist, neuroimmunologist, and researcher at Sutter Health’s Palo Alto Medical Foundation in California, says the strongest genetic risk factors for MS increase a person’s risk by tenfold. In other words, the risk goes from approximately 0.1 percent to 1 percent if you have these risk factors, which is still very low.
What About Family History?
If you have an identical twin who has MS, you still only have about a 25 percent of developing the disease. The risk also increases when you have other close relatives (parents, siblings, and children) who have MS, but significantly less than in identical twins.
“There’s an increase, but not a guarantee,” of developing MS when a family member has it,?Dr. Greenfield?says.
Gender and the Risk of Developing MS
But equal numbers of women and men are affected by?primary-progressive MS, a less common type — or possibly stage — of MS associated with more disability.
Women’s greater susceptibility to MS overall is thought to be associated with hormonal changes, Dr.?Mateen?says.
Other Possible Contributing Causes of MS
There are a number of other factors that are associated with an increased risk for developing multiple sclerosis, although whether any of them are causative is unknown.
Smoking
Low Levels of Vitamin D
In response to such studies, many doctors have begun recommending vitamin D supplements for people who have MS, particularly for those who are vitamin D deficient.
Geographic Location
People who live in more temperate climates — like Europe, southern Canada, and the United States — have a slightly higher risk of MS than those who live closer to the equator, Greenfield says.
RELATED:?Why Your ZIP Code Matters if You Have Multiple Sclerosis
Obesity
Having an Autoimmune Condition
Mateen says that while these other conditions don’t cause MS, if you have one autoimmune disease, you have a higher risk of getting a second one, and?MS is generally considered an autoimmune disease.
Epstein-Barr Virus
RELATED:?What Does the Epstein-Barr Virus Have to Do With MS?
Concussion in Adolescence
While there’s more to be learned about the connection between MS and concussion, the researchers commented that their results emphasized the importance of?protecting young people from head injuries.
Race
Age
Living Near Major Roads
Living near green spaces, however, was found to have some protective effects against MS and the other disorders.
Can You Prevent Your Family Members From Getting MS?
Mateen is often asked by patients if their family members are at greater risk for MS and what they can do to reduce their chances of getting it. Unfortunately, she says,?there isn’t a lot you can do to prevent the disease.
“With MS, there isn’t a lot to monitor or evidence that if you change your diet or lower stress or exercise regularly you have less chance of developing it,” she says.
But she does have some advice for family members of persons with MS:
- If you have a symptom that might be caused by MS, get it checked out.
- Avoid smoking and?secondhand smoke.
- Try to maintain a healthy weight and make sure you’re getting enough vitamin D.
“People should stay mentally and physically active so if someone does get MS, they will have greater physical and mental reserves to deal with it,” Mateen says.
RELATED: Can You Prevent Multiple Sclerosis?
Resources We Love
National Multiple Sclerosis Society
The National Multiple Sclerosis Society is a nonprofit organization that aims to find a cure for MS. It also provides information about symptoms, diagnosis, treatment, resources, and support for MS.
Mayo Clinic
The Mayo Clinic is a nonprofit organization that specializes in clinical practice, education, and research. Its website offers information about the symptoms, causes, risk factors, complications, diagnosis, and treatment of MS.
Multiple Sclerosis Association of America
MSAA is a nonprofit organization dedicated to improving the lives of people with MS through ongoing support and services. The organization offers free services such as a helpline with MS specialists and tools to help manage the disease.
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Sources
- Definition of Multiple Sclerosis. National Multiple Sclerosis Society.
- What Causes MS? National Multiple Sclerosis Society.
- Primary Progressive MS (PPMS). National Multiple Sclerosis Society.
- Low Testosterone Is Associated With Disability in Men With Multiple Sclerosis (PPMS). Multiple Sclerosis Journal.
- Unhealthy Habits. National Multiple Sclerosis Society.
- The Risk of Smoking on Multiple Sclerosis: A Meta-Analysis Based on 20,626 Cases From Case-Control and Cohort Studies. PeerJ.
- 25-Hydroxyvitamin D Deficiency and Risk of MS Among Women in the Finnish Maternity Cohort. Neurology.
- Multiple Sclerosis: Symptoms and Causes. Mayo Clinic.
- Concussion in Adolescence and Risk of Multiple Sclerosis. Annals of Neurology.
- Incidence of Multiple Sclerosis in Multiple Racial and Ethnic Groups. Neurology.
- Who Gets Multiple Sclerosis? Epidemiology of MS. National Multiple Sclerosis Society.
- Road Proximity, Air Pollution, Noise, Green Space and Neurologic Disease Incidence: A Population-Based Cohort Study. Environmental Health.
Resources
- Definition of Multiple Sclerosis.?National Multiple Sclerosis Society.
- What Causes MS??National Multiple Sclerosis Society.
- Primary Progressive MS (PPMS).?National Multiple Sclerosis Society.
- Bove R, Musallam A, Healy BC, et al. Low Testosterone Is Associated With Disability in Men With Multiple Sclerosis.?Multiple Sclerosis Journal. October 2014.
- Unhealthy Habits.?National Multiple Sclerosis Society.
- Zhang P, Wang R, Li Z, et al. The Risk of Smoking on Multiple Sclerosis: A Meta-Analysis Based on 20,626 Cases From Case-Control and Cohort Studies. PeerJ. March 15, 2016.
- Munger KL, Hongell K, Aivo J, et al. 25-Hydroxyvitamin D Deficiency and Risk of MS Among Women in the Finnish Maternity Cohort.?Neurology.?October 10, 2017.
- Multiple Sclerosis: Symptoms and Causes.?Mayo Clinic. December 24, 2022.
- Montgomery S, Hiyoshi A, Burkill S, et al. Concussion in Adolescence and Risk of Multiple Sclerosis.?Annals of Neurology. October 2017.
- Who Gets Multiple Sclerosis? Epidemiology of MS.?National Multiple Sclerosis Society.
- Yuchi W, Sbihi H, Davies H, et al. Road Proximity, Air Pollution, Noise, Green Space and Neurologic Disease Incidence: A Population-Based Cohort Study.?Environmental Health.?January 21, 2020.
- Langer-Gould A, Brara S, Beaber B, Zhang J. Incidence of Multiple Sclerosis in Multiple Racial and Ethnic Groups. Neurology. May 7, 2013.
Jason Paul Chua, MD, PhD
Medical Reviewer
Tammy Worth
Author
As a freelancer, she has written for outlets including The Economist, Bloomberg, Health.com, Leader’s Edge, WebMD, and KCPT, Kansas City’s public television station. For several years, Worth wrote a healthcare column in the Los Angeles Times called Practical Matters.
Worth received a bachelor’s degree in English from the University of Missouri in Kansas City and a master’s degree in journalism from Northeastern University in Boston.