Multiple Sclerosis Centers of Excellence
How Common Is Multiple Sclerosis and Possible Causes
Multiple sclerosis (MS) is one of the most common causes of disability in young adults, and close to 1 million people in the United States are living with it. MS is about three times more common in women than in men, and it is more common in the northern parts of the country than in the south. No one knows exactly what causes MS, but research has taught us a lot about who gets it and why.
How do we know how many people have MS?
For many years, no one knew the exact number. A large study published in 2019, done in part by the VA, gave us a better one. Researchers reviewed health records from more than 100 million adults, including Veterans, and estimated that close to 1 million people in the United States have MS. That is far more than the 400,000 estimated in 2000. The number is higher now partly because people with MS are living longer, and because the disease is found and diagnosed earlier than it used to be.
Does MS run in families?
MS is not passed straight from parent to child, and it is not caused by a single faulty gene. Researchers have found more than 100 small gene changes that may each add a little to the risk, but having them does not mean you will get MS. MS can still show up more than once in a family. In the general population, the chance of getting MS is low, about 1 to 2 people in 1,000. If a parent, brother, sister, or child has MS, the chance is higher, around 1 in 35. For an identical twin of someone with MS, it is about 1 in 4. Even so, most close relatives of people with MS never develop it.
What in the environment raises the risk?
The rest of the risk seems to come from the environment. Vitamin D and sunlight appear to play a role: MS is more common the farther you live from the equator, where there is less sun, and low vitamin D early in life may raise the risk. The Epstein-Barr virus, a common virus that causes mono, has also been linked to MS. Smoking raises the risk of getting MS, and in people who already have it, smoking can speed the disease and lead to more disability. Extra weight in childhood and the teen years, especially in girls, is tied to a higher risk later. Heart health matters too: high blood pressure, high cholesterol, and diabetes are linked to worse MS outcomes.
Can you lower the risk for your children?
You cannot change the genes you pass on, but some of these risk factors are within your control. If you have MS, it is worth talking with your children about not smoking, staying at a healthy weight, and getting enough vitamin D. These are healthy habits for everyone, and they may lower the chance of MS. (See also: What Is MS? for more on the disease and its types.)
Does military service cause MS?
Some brain and nerve diseases, such as ALS, have been linked to military service. So far, research has not found that link with MS.
When to Talk to Your Provider
If MS runs in your family, or you have questions about your own risk factors, bring them up with your health care team. Your VA provider can check your vitamin D level, help you manage blood pressure, cholesterol, and weight, and connect you with the VA smoking cessation program if you smoke. These steps support your overall health and may lower MS risk for you and your family.
