• Geographic location, or where you lived during childhood (up to age 15). People who spend the first 15 years of their lives in colder climates that are farther away from the equator tend to be more likely to get MS than people who lived closer to the equator during those years.
• Family history of MS. About 15 out of 100 people who have MS have a relative with MS, most often a brother or sister.²
• Certain genetic characteristics associated with the immune system. These appear more frequently in people who have MS. This may mean that there are one or more genes that may increase the chance of getting MS.
• Race. People of Western European ancestry are more likely to get MS.
• Being female. MS is about 3 times as common in women as in men.

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