The number of people living with multiple sclerosis (MS) today is higher than it's ever been. MS is the most common disabling condition affecting the central nervous system among young adults. The global prevalence of the autoimmune disease is approximately 2.5 million people. MS affects around 1 million people in the United States and 130,000 people in the United Kingdom. In the U.K., the incidence of MS diagnosis is an estimated 100 people per week.

Several factors are likely contributing to this apparent surge in MS diagnoses, and there are steps people can take to reduce their own chances of developing the condition.

What Do These New Multiple Sclerosis Figures Mean?

Before a landmark 2019 study analyzed health care data to identify cases of MS, estimates of the condition’s prevalence were around 400,000 people in the U.S. Today’s figure is more than double the previous estimate. Although research does suggest that MS may be on the rise outside the U.S., experts offer several other explanations for why the net number has jumped — including the arrival of better diagnostic tools and the fact that the global population has grown.

Better Diagnostic Tools

Neurologists have become better at diagnosing MS thanks to advances in medicine, a vastly greater understanding of MS gleaned through clinical trials and research, and breakthroughs in the field of neurology — such as the advent of MRI scans. MRI scans allow for more accurate diagnosis and monitoring of the course of MS, but MRI had not been used for diagnosis at the time of original prevalence estimates. Analyzing a person’s cerebrospinal fluid for tell-tale abnormalities also improves the diagnostic accuracy of MS.

Population Growth

In 2019, the world population was estimated around 7.7 billion people. In the 1970s, when the number of people living with MS was estimated to be in the 400,000 range, the world population was 3.6 billion. With the population more than doubling since the last MS prevalence rate was estimated, population growth could explain the rise in the cases of MS in the most recent survey.

Better Tracking and Data Collection

Experts now have better tools at their disposal for estimating how many people have MS. A complex algorithm was used to calculate the most recent estimate of MS prevalence in the U.S. This algorithm likely captures a majority of those who see a health care provider for MS treatment.

Congress has also passed the 21st Century Cures Act. This piece of legislation authorizes the Centers for Disease Control and Prevention to create and populate a registry of neurological diseases, MS included. This data-collection effort, called the National Neurological Conditions and Surveillance System, can potentially answer many questions about MS and fund more research.

Additionally, the North American Research Committee on Multiple Sclerosis (NARCOMS), an MS registry, boasts a database of 41,000 (and growing) people living with MS. The registry will hopefully enable experts to learn about the rate of MS diagnosis, disease course, disease progression, and disability. If you are living with multiple sclerosis, consider adding your information to the NARCOMS registry.

Can Multiple Sclerosis Be Prevented?

MS is not currently a preventable disease. Scientists still don’t fully understand what causes multiple sclerosis, nor do they know exactly how to halt disease progression or the worsening of MS lesions on the brain and spinal cord. But they’re closer than ever.

Ultimately, preventing MS will require a greater understanding of the condition’s autoimmune pathology, specifically how MS causes attacks on myelin, the demyelination of nerve cells, and injury to nerve fibers. These all result in MS symptoms, contribute to longer-term disability, and cause irreversible neurological damage and dysfunction.

Risk Factors and Protective Factors

Although MS can’t be prevented, a person can help reduce their risk of developing MS by avoiding or limiting exposure to known risk factors, especially environmental factors. A risk factor for MS is something that makes you more susceptible to developing MS. It is thought that the more factors a person has, the greater their lifetime risk of developing MS. You can also help reduce your susceptibility by introducing or increasing the number of protective factors in your lifestyle to help offset some risk factors.

Some estimates suggest that the lifetime risk of developing MS among the general population is 1 in 330. Some risk factors linked to developing MS are outside of a person’s control, including:

• Genetics
• Family history of MS
• Other autoimmune diseases, like rheumatoid arthritis
• Certain viral infections, such as Epstein-Barr virus

Other risk factors, however, are modifiable.

Healthy Weight, Diet, and Regular Exercise

Research suggests that obesity, or having a high body mass index, could be a risk factor for multiple sclerosis. Maintaining a healthy weight through eating a healthy, balanced diet and getting regular exercise may reduce the risk of MS.

Vitamin D and Sun Exposure

Vitamin D deficiency has been linked to MS. Vitamin D is manufactured by the skin when we’re exposed to sunlight. Research suggests that ample vitamin D levels, whether through sun exposure or supplementation, may delay or prevent clinically isolated syndrome (CIS) or a first demyelinating event. For example, a large cohort study showed that women who either had more vitamin D in their diet or took vitamin D supplements have a lower incidence of MS. Also, it’s known that populations exposed to greater amounts of sunshine or ultraviolet radiation have lower rates of MS.

More studies are under way to investigate the role of vitamin D as a protective agent against the development of MS and as a treatment for people with the condition.

Smoking Cessation or Reduction

Smoking increases the risk of getting MS, especially the longer and more you smoke. The risk of MS to smokers is 1.5 times higher than for those who do not smoke or never have. Even ex-smokers and secondhand (passive) smokers are at higher risk of MS than nonsmokers, though not as high of a risk as current smokers.

Smokers who already have MS are also at a greater risk of experiencing more rapid disease progression to more aggressive forms of MS than nonsmokers, such as progressing from CIS to relapsing-remitting MS (RRMS) or from RRMS to secondary progressive MS.

The good news is it's never too late to quit the habit. A person’s MS risk declines the more time that passes since quitting smoking. Studies suggest that efforts to reduce tobacco use help lower the risks associated with smoking status and MS.

Find Your Team

If you’re among the growing number of people with MS, it may help to build a community and connect with others who understand life with MS. MyMSTeam is the social network for people living with MS and their loved ones. More than 164,000 people come together to give advice, ask questions, and share their experiences living with MS.

Are you living with MS? Share your experience in the comments below, or start a conversation by posting on MyMSTeam.