Can You Prevent Multiple Sclerosis?

Scientists are beginning to understand what raises a person’s risk of MS, but how close are they to finding ways to prevent it?
Can You Prevent Multiple Sclerosis?
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Updated on May 28, 2024
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The past few decades of multiple sclerosis (MS) research have led to a greater understanding of why some people develop this chronic autoimmune disease. Experts have identified several risk factors for MS, including some that could be controlled.

So does that mean that the nearly one million people living with MS could have avoided getting this chronic autoimmune disease?

Based on what experts know about MS, the answer is no — or at least not yet. One reason that effective prevention measures have yet to be developed is that there’s no one thing that we know of that causes MS, says Cole Harrington, MD, PhD, a neurologist at the Ohio State University Wexner Medical Center in Columbus.

“It’s thought that MS is caused by a combination of genetic and environmental factors,” says Dr. Harrington. There is also evidence to suggest that people at risk of developing MS have differences in their immune system, Harrington says.

“Hopefully in the future we can develop ways to prevent MS. We are not there yet, but I think we are getting closer to developing biomarkers and other ways of catching MS early and preventing it,” Harrington says.

Genetics and Family History Affect Your Risk

If you have a family member with MS, you're at higher risk for the disease yourself. Tanuja Chitnis, MD, a professor of neurology at Harvard Medical School and the director of the Mass General Brigham Pediatric MS Center at Mass General Hospital for Children, both in Boston, says that in studies of identical twins, about 25 percent of people who have an identical twin with MS end up with MS.

People with a parent, non-twin sibling, or child with MS also have a higher risk. According to the National Multiple Sclerosis Society, while the average person in the United States has a 0.1 percent chance of developing MS, the risk rises to 2 to 5 percent for first-degree relatives of people with MS.

The International MS Genetics Consortium (IMSGC), an international academic research group, analyzed genetic data and found 233 human genomic variations that are implicated in MS.

 Genetic variants alone, however, don’t predict the development of MS. Environmental factors — a virus, a lack of vitamin D in the body, smoking, or something else entirely — also appear to affect your risk.

Common Viruses May Raise Your Risk of MS

It’s thought that there are probably things that set off the immune system that can cause someone to develop MS, says Harrington.

Decades of research showed a link between Epstein-Barr virus (EBV), a member of the herpes family of viruses, and MS, although it had not conclusively been identified as a cause. A review of research states that despite years of controversy, the role of EBV infection and seropositivity (the presence of antibodies in the blood) as cofactors for most forms of MS “may now be settled.” The severity of the EBV infection strongly correlates with the development of MS many years later, researchers note, so it’s likely that MS depends on how the immune system initially responds to the infection.

One study found that every single patient selected from a database of people with early MS tested positive for antibodies to EBV. The authors concluded that if a person is suspected to have MS but has negative EBV serology, a diagnosis of a condition other than MS should be considered.

EBV is extremely common: the Centers for Disease Control and Prevention reports that most people get infected with this virus at some point in their lives.

 In children, EBV looks just like the common cold; in adolescents and adults, it can develop into mononucleosis, which typically causes severe fatigue, fever, muscle aches, sore throat, and swollen lymph nodes in the neck and armpits. But not all of these people have genetic predispositions associated with MS.
Another common virus that's been linked to MS is human herpesvirus 6 (HHV-6), according to the National Multiple Sclerosis Society.

 Research has shown that higher HHV-6 antibody levels in the body were associated with an increased risk of MS relapses.

Although HHV-6 has not been shown to trigger the onset of MS, there is growing evidence that HHV-6A, a type of HHV-6, may have a role in MS development. One study discovered that antibodies contained in the blood showed that people with MS carry the herpesvirus 6A to a greater extent than people without MS.

Where You Live, Sun Exposure, and Vitamin D Levels May Make MS More Likely

The incidence of MS is higher in North America, southern Australia, and northern Europe, suggesting that people who live farther from the equator have a greater risk, says Harrington.

This may be related to sun exposure and vitamin D levels in the body. Vitamin D is known as the sunshine vitamin because the human body generates it in response to sunlight.

One study found that women who had deficient levels of vitamin D — defined in the study as fewer than 30 nanomoles per liter — were 43 percent more likely to develop MS than those with normal levels of the vitamin.

According to a review of research, the existing evidence on vitamin D and MS suggests that normal vitamin D levels reduce the risk of MS and affect the course of the disease, but additional studies are needed to confirm and understand this association.

“Vitamin D deficiency is associated with a higher risk of developing MS, but that alone doesn’t cause MS. We check the level of vitamin D in people with MS, and we supplement if it’s too low,” says Harrington.

Smoking Is Associated With an Increased Risk of MS

There is evidence that the risk of MS is higher in former or current smokers, says Harrington. In general, smokers develop more autoimmune conditions, says Cleveland Clinic, and MS is considered an autoimmune condition.

A meta-analysis of research estimated the risk of MS was increased by 50 percent in “ever smokers” (versus never-smokers). The researchers also found that passive exposure to smoking was a risk factor for MS in non-smoking populations.

“Smoking is also associated with having a worse outcome if you have MS; we recommend if someone with MS is a smoker, that they stop,” says Harrington.

Childhood Obesity Could Be a Factor in the Development of MS

Although we can’t go back in time and change our past weight or diet, there is evidence that childhood obesity is a risk factor for MS, says Harrington.

One study strengthened the findings of existing research on this relationship through a method called Mendelian randomization. By examining genetic variants, investigators determined that body mass index before age 10 is an independent causal risk factor for the development of MS.

Gut Microbiome May Play a Role in MS

Gut health and the gut-brain connection are increasingly thought to be relevant to the development of MS.

A study from the International MS Microbiome Study Consortium found that the gut microbiome — the millions of bacteria and microorganisms in the intestines — was associated with MS risk and disease stage. According to the study authors, their “findings strongly support” associations between the gut microbiome and the course of MS. It’s not yet clear how, exactly, these associations work. But researchers note this “study supports the possibility that microbial manipulation and dietary intervention could be used as preventive and therapeutic strategies in MS.”

Additional reporting by Becky Upham and Deborah Shapiro.

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Jason Paul Chua, MD, PhD

Medical Reviewer
Jason Chua, MD, PhD, is an assistant professor in the Department of Neurology and Division of Movement Disorders at Johns Hopkins School of Medicine. He received his training at the University of Michigan, where he obtained medical and graduate degrees, then completed a residency in neurology and a combined clinical/research fellowship in movement disorders and neurodegeneration.

Dr. Chua’s primary research interests are in neurodegenerative disease, with a special focus on the cellular housekeeping pathway of autophagy and its impact on disease development in diseases such as Parkinson disease. His work has been supported by multiple research training and career development grants from the National Institute of Neurological Disorders and Stroke and the American Academy of Neurology. He is the primary or coauthor of 14 peer-reviewed scientific publications and two peer-reviewed online learning modules from the American Academy of Neurology. He is also a contributing author to The Little Black Book of Neurology by Osama Zaldat, MD and Alan Lerner, MD, and has peer reviewed for the scientific journals Autophagy, eLife, and Neurobiology of Disease.
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Connie Brichford

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Connie is Boston-based freelance writer who focuses on science and current events. Her interests include child development, science literacy for children and adults and the intersections of feminism and pop culture.

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