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Who Gets MS? (Epidemiology)

While MS is not contagious or directly inherited, epidemiologists have identified factors in the distribution of MS around the world that may eventually help determine what causes the disease.

Diagnosed in 1995


In this article

How many people live with MS?

Nearly 1 million are living with MS in the United States, according to a study funded by the National MS Society.


Epidemiology is the branch of medicine that deals with the incidence, prevalence, distribution and possible control of diseases and other factors relating to health.
While multiple sclerosis is not contagious or directly inherited, epidemiologists — scientists who study patterns of disease — have identified factors in the distribution of MS around the world that may eventually help determine what causes the disease. These factors include gender, genetics, age, geography and ethnic background.
Graphic - Society-led study confirms nearly 1 million people living with MS in the U.S., twice as many as the previous estimate. Map of U.S. shows prevalence by region per 100,000 residents: Northeast 377, Midwest 353, South 277, West 277  Graph shows prevalence by gender: 1976 estimate: 37 percent male, 63 percent female. 2017 estimate, 74 percent female, 26 percent male.
Age: Most people are diagnosed between the ages of 20 and 50, although MS can occur in young children and older adults.

Geography: In general, MS is more common in areas farthest from the equator. However, prevalence rates may differ significantly among groups living in the same geographic area regardless of distance from the equator.
Gender: The recent prevalence study shows MS is three times more common in women than in men, suggesting that hormones may also play a significant role in determining susceptibility to MS.
Ethnic Background: Research has demonstrated that MS occurs in most ethnic groups, including African Americans, Asians and Hispanics/Latinos, but is most common amongst Caucasians of northern European ancestry. Susceptibility rates vary among these groups, with recent findings suggesting that African American women have a higher than previously reported risk of developing MS.

Epidemiological estimates

Although more people are being diagnosed with MS today than in the past, the reasons for this are not clear. Likely contributors include greater awareness of the disease, better access to medical care and improved diagnostic capabilities. There is no definitive evidence that the rate of MS is generally on the increase.

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