Multiple sclerosis is a disease that affects the central nervous system that includes the brain and the spinal cord. In MS, the protective layer of the neurons called the myelin is attacked by the immune system, thereby disabling neuronal communication between the brain and the rest of the body. Where a person lives and the ages at which they are exposed to the sun''s rays may play an important role in reducing the risk of multiple sclerosis (MS), according to a new study. People who live in sunnier climates and are more exposed to the sun''s rays are less likely to develop MS later in life.