Multiple sclerosis affects about 400,000 people in the United States, and about 2 1/2 million worldwide. In the United States, the prevalence of the condition — that is, the number of people who have it compared with the general population — is nearly 90 cases per 100,000 people.

The prevalence of MS varies with location and increases with distance from the equator. We don’t know whether this has to do with an environmental influence, a genetic influence, or something else.

MS usually shows up when a person is between 20 and 40 years of age, with 32 the mean age. It can occur in young children, however.

MS is more common is women than men, with recent studies suggesting a female to male ratio as high as three to four women with MS against one man.

The last study of the prevalence of MS in the United States was in 1975. This is mainly because the Centers for Disease Control and Prevention do not require U.S. health practitioners to report new cases. Since MS is sometimes invisible — that is, its symptoms are not showing — the U.S. prevalence of MS can only be estimated. The National MS Society is trying to establish a registry to track the number of people with MS. It has also made a commitment to re-evaluating and updating the numbers.


Note: Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.