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Searching for Triggering Factors

Pursuing the question of “who gets MS” has led us down several promising paths, and the Society continues to search for and find the answers that will end this disease.


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Searching for Triggering Factors: Who gets MS?

Pursuing the question of “who gets MS” has led us down several promising paths, and the Society continues to search for and find the answers that will end this disease. Research of populations to study disease patterns, including variations in geography, demographics, socioeconomic status, genetics, environmental risk factors, and exposure to infectious agents, is called “epidemiology.” These studies provide vital information about relationships among these factors, so that we can better understand who gets MS and why, identify and explain areas with high or low rates of the disease, and assist in planning for health care and other services.

Epidemiologic studies have given us some important clues about who develops MS:

  • The disease affects more than twice as many women as men. Read more about how gender research has led to treatment trials. 
  • It is most common among people with a northern European heritage, but people of other backgrounds develop the disease as well. Read more about research that is expanding our views on MS in African Americans and Hispanic Latinos.
  • MS appears to be more prevalent in temperate regions of the world than in the tropics leading to research on the effects of exposure to sunlight and vitamin D. Read more
  • It is diagnosed most often in people between the ages of 20 and 50, although it also can develop quite early or quite late in life. Read more about how the Society has changed the experience of children and adolescents with MS.
  • Although no virus has been pinpointed to cause MS, intriguing research on viruses continues. Read more
  • Substantial evidence exists that smoking can increase a person's chances of developing MS, and also worsens MS. Read more

Driving collaborations worldwide

Risk factor research often requires large, major studies. The Society is moving such studies forward, faster:

The SUMMIT study: SUMMIT (Serially Unified Multicenter Multiple Sclerosis Investigation) is an innovative and ambitious research project with the goal of providing a tool that will unravel why and how MS progresses, with the goal of predicting and preventing progression. This 5-year study brings together two MS Centers of Excellence: Harvard’s Brigham and Women’s hospital and the University of California, San Francisco. Each institution has been carefully following MS cohorts for nearly 10 years, amassing deep collections of information, clinical data, MRI images, questionnaires and biological specimens involving over 1,000 people with MS. The SUMMIT investigators will recruit and track new and existing participants with annual clinical assessments, bloodwork, MRI and other tests, to develop an extensive, open database of clinical information that clinicians and researchers have needed and wanted for years.

Why do kids get MS? Investigators nationwide are recruiting 640 children with early relapsing-remitting MS or CIS (clinically isolated syndrome, a single episode of MS-like symptoms) and 1280 children without MS or CIS for a four-year study to determine environmental and genetic risk factors that make children susceptible to developing MS. The study, funded by the National Institutes of Health, leverages the National MS Society’s support of the Network of Pediatric MS Centers. Read more

Studying family: Researchers from the Harvard Medical School, Brigham and Women’s Hospital, and Partners Multiple Sclerosis Center, in collaboration with the National Institute of Neurological Disorders and Stroke (a branch of the National Institute of Health, NIH), are recruiting 5,000 subjects who have at least one first-degree relative with a diagnosis of MS.  The goal of the study is to identify the genetic, environmental and immune profiles that may increase a person’s risk of developing MS.  A first-degree relative could be a parent, sibling, or child of a person with MS, and the study is limited to those between 18 and 50 years of age. The GEMS (Genes and Environment in MS) study is not funded by the Society, but is led by primary investigator Philip De Jager, MD, PhD, a Harry Weaver Neuroscience Scholar of the National MS Society. Read more


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