Recent research shows that the Epstein-Barr virus (EBV) may be the leading cause of multiple sclerosis (MS), an autoimmune disease in which a person’s immune system attacks and destroys the myelin (protective coating) surrounding their nerves.

Additional research shows that the combination of EBV infection with other risk factors — low vitamin D levels and smoking, in particular — may have an even greater impact on a person’s risk of developing MS. Many people who have these risk factors may never develop MS, and there are still things scientists do not understand about this autoimmune condition.

In some people who are genetically predisposed, however, having these three risk factors may create a “perfect storm” for developing multiple sclerosis. Here’s what to know, including how to reduce your risk from these factors and how to improve your outcome if you do develop MS.

Risk Factors for Multiple Sclerosis

Several factors may increase the risk of developing MS. Genetic risk factors for MS include certain inherited genes that are involved in immune system function. Some gene variants, such as variants of HLA-DRB1, may also interact with environmental factors to increase someone’s MS risk.

In addition to genetic risk factors, several environmental risk factors for MS have also been identified, including Epstein-Barr virus infection, smoking, and low vitamin D levels. The combination of genetic factors with these environmental factors appears to increase a person’s MS risk significantly.

Epstein-Barr Virus

Infection with EBV can increase MS risk, especially if the virus caused infectious mononucleosis (mono). Infections of EBV occur in over 90 percent of the adult population worldwide, so simply having had EBV does not appear to increase risk, not unless other risk factors are present. While EBV does not always cause significant symptoms, it can cause infectious mononucleosis in teens and young adults.

Interestingly, some variants of HLA-DRB1 (a gene that may increase MS risk) have been shown to correlate with someone carrying a higher viral load of EBV.

Smoking

Cigarette smoking increases a person’s risk of MS and many other diseases, including heart disease, lung disease, cancer, and a variety of autoimmune diseases. Smoking can also increase someone’s MS disease activity and contribute to worse symptoms, more relapses, greater disability, and higher risk of disease progression.

Vitamin D

Vitamin D deficiency is linked to an increased MS risk. Such a deficiency can be caused by lack of sufficient sun exposure needed for the body to make vitamin D in the skin. Vitamin D is needed for proper immune function, calcium absorption, and other functions. Like smoking, having low levels of vitamin D may be associated with an increased risk of MS progression.

Other Environmental Risk Factors

EBV infection, smoking, and vitamin D deficiency appear to be the biggest contributors to MS risk, but other factors are also important.

There is strong evidence that obesity during adolescence and young adulthood can raise a person’s MS risk, and that it is associated with an earlier onset of the condition. Additional possible risk factors include exposure to certain chemicals, including organic solvents, and working during the night shift. Research into the causes of MS is ongoing and will likely continue to find more potential risk factors.

Reduce Your Risk

While you cannot control the genes you inherit from your parents, you often do have some control over environmental exposures.

Quit Smoking

If you smoke, quitting smoking may be one of the simplest ways to decrease your MS risk or to improve your outcome if you already have MS. Quitting is not always easy, so enlist the help of your health care team to find the methods that are most effective for you.

Get Enough Vitamin D

Ideally, a healthy diet and plenty of sunlight should provide you with all the vitamin D you need. Talk to your doctor about checking your vitamin D status with a simple blood test. If you are not getting enough vitamin D, then you can talk to your doctor about your options. The doctor may advise you to take prescription or over-the-counter vitamin D supplements. Before taking supplements — even natural ones — be sure to always discuss them with your doctor.

Maintain a Healthy Body Weight

Maintaining a healthy body weight can help improve MS symptoms. You can calculate your body mass index (BMI) to assess whether or not you are at a healthy weight. While BMI is an imperfect measurement of health, it can be a good place to start.

Getting proper nutrition and exercise are essential parts of weight loss and staying healthy in general. Talk to your doctor or another trusted health care professional about eating healthily, exercising, and losing weight, especially if you carry excess weight.

Talk With Others Who Understand

MyMSTeam is the social network for people with MS and their loved ones. On MyMSTeam, more than 182,000 members come together to ask questions, give advice, and share their stories with others who understand life with MS.

Do you think smoking, your vitamin D levels, and the Epstein-Barr virus might have contributed to your MS? Share your experience in the comments below, or start a conversation by posting on your Activities page.