Multiple Sclerosis

Variety of factors increase risk of developing MS

DEAR MAYO CLINIC: What causes multiple sclerosis, or MS, in people who don't have it in their family?

ANSWER: The exact cause of MS isn't known. But it's clear that a variety of factors can increase a person's risk of developing this disease. Along with genetics, those risk factors include age, sex, a medical history of certain infections or diseases, race, and the climate where you live.

MS is a potentially disabling disease of the central nervous system, which includes the optic nerves; the white matter of the brain and back of the brain, called the cerebellum; the brainstem, which is the lowest part of the brain; and the spinal cord. The nerves that travel from the spinal...