Multiple Sclerosis Health Article

Definition

Multiple sclerosis is a chronic, degenerative disease of the central nervous system (CNS). The CNS is comprised of the brain and the spinal cord. In the CNS, the nerves are covered by a protective layer called the myelin sheath. Myelin helps keep the nerve healthy. It also improves nerve conduction. In multiple sclerosis, inflammation causes the nerves to gradually lose this myelin cover. This repeated inflammation and erosion leads to scarring (sclerosis), which impairs the nerve's ability to conduct impulses. Eventually, even the nerves themselves are affected. Because the nervous system controls and coordinates a number of body functions, patients with MS gradually lose a variety of functions, including memory and the ability to see, speak or walk.

Description

Multiple sclerosis is a chronic debilitating disease that affects as many at 350,000 in the United States alone (2.5 million worldwide). Most patients are first diagnosed of the disease at age 20-40. However, the disease may appear as early as age 12 or as late as age 50. MS strikes women earlier in life. Women are also affected more frequently than men and whites more often than other races.

Causes & symptoms

The causes of multiple sclerosis are still unknown, although many factorsare suspected. In the United States, whites are diagnosed with MS twice as often as blacks or Hispanics. Asians are the least affected. There is some consensus, however, that the following factors may contribute to the development of multiple sclerosis:

• Genetic heredity. Family members of multiple sclerosis patients have a 1 in 50 chance of having MS; the odds for people without an affected family member are 1 in 1,000. If an identical twin is diagnosed with MS, the remaining twin has a 1 in 3 chance of becoming affected as well. Recent research has shown that several autoimmune diseases, including MS, share a common genetic link. In other words, patients with MS might share common genes with family members that have other autoimmune diseases like systemic lupus, rheumatoid arthritis, and others.

• Viral infection. Most MS patients have high levels of antibodies to measles and other viruses. Therefore, multiple sclerosis may be the body's delayed immune reaction to viruses such as measles, Herpes simplex, rubella, and parainfluenza. A 2001 study also suggested that Epstein-Barr virus, the virus that causes mononucleosis, probably increases risk of MS.
• Autoimmune reaction. Scientists know that MS is an autoimmune disorder, an illness in which the body attacks its own myelin as if it were a foreign substance. Although research has identified which immune cells are responsible and how they are activated, no one knows what causes the immune system to begin this attack.
• Geography. Countries in the temperate zones (above 40°) such as Northern Europe, North America, Australia, and New Zealand have significantly higher incidence of multiple sclerosis than countries in the tropics. In the United States, people who live below the 37th parallel develop MS at a rate of 57–78 cases per 100,000 people. Those who live above the line have a prevalence rate of 110–140 cases per 100,000 people.
• Diet. Studies have shown that populations at high risk of developing multiple sclerosis tend to consume a lot of dairy products and animal fats. On the contrary, in countries such as Japan, people eat few dairy products but consume lots of fish, soy-rich foods, and seeds, which are good sources of essential fatty acids. The incidence rates in these countries are very low. Thus, essential fatty acid deficiency due to excessive consumption of saturated fats may contribute to the development of multiple sclerosis.