What Is MS?
Multiple Sclerosis (MS) is a chronic disease of the central nervous system (CNS), which is made up of the brain, spinal cord, and optic nerve. The nerves in the CNS are surrounded by a protective fatty material called myelin.1
In MS, it is believed that when the immune system attacks the CNS, the myelin is damaged - resulting in the formation of dense, scar-like tissue. These scars (also known as lesions) occur in many places throughout the CNS, hence the name "multiple sclerosis", or many scars.1
The scar tissue affects the way electrical impulses travel along the nerve fiber, distorting and interrupting signals coming to and from your brain and spinal cord. This may result in symptoms that could be mild, such as numbness in the limbs, or severe, such as paralysis or loss of vision. The progress, severity, and specific symptoms of MS are unpredictable and vary from one person to another.1
Who Gets MS?
Worldwide, 2.5 million people have been diagnosed with MS. MS is most prevalent in northern Europe, North America, South-East Australia and New Zealand. It is least prevalent in tropical and sub-tropical regions.2 In the US, approximately 10,000 to 15,000 new cases are diagnosed every year.3
The chance of getting multiple sclerosis, on average, is 1 in 750. If someone in your immediate family has MS, your chance of developing MS may increase. MS is not directly hereditary, although genetic susceptibility plays a part in its development. Factors like geography, ethnicity, and maybe even infection can affect whether someone develops multiple sclerosis.4
Multiple sclerosis is most commonly diagnosed between 20 and 50 years of age, although onset may be earlier.5 While anyone can get MS, it is 2 to 3 times more common in women than in men. MS occurs in most ethnic groups but is more common among people of northern European descent.4
Learn more about Symptoms & Diagnosis and Treatment Options or check out A Peer's Perspective.
Causes and Risk Factors5,6
While it is not known what causes MS, it is known that MS is not a result of lifestyle choices and it's not contagious. The current theories about causes of the disease include:
- Immunology. The body's immune system responds in an abnormal way by attacking the myelin in the central nervous system. Although it's not known what target the immune cells are attacking, scientific research has identified which immune cells are doing the attacking and some of the factors for doing so.
- Environment. Variations in geography, demographics (age, gender, and ethnic background) are being studied. Studies suggest that low levels of vitamin D, which is thought to aid proper functioning of the immune system, as well as exposure to certain agents, may play a role in the development of MS.7
- Infections. Viral and bacterial infections may trigger MS. Research is being done on many viruses to see if any play a role in MS.
- Genetics. Although people with MS do not inherit the disease, there is some increased risk of its occurrence among family members. Scientists are looking at certain genes that are shared within families affected by MS or found in patient populations with higher rates of MS.
References
- What is multiple sclerosis? National Multiple Sclerosis Society Web Site. http://www.nationalmssociety.org/about-multiple-sclerosis/what-is-ms/index.aspx. Accessed April 13, 2010.
- Who Gets MS? MS-Network Web Site. http://www.ms-network.com/intl/msnetwork/general/guide_understanding_ms/
what_is_ms/who_gets_ms/who_gets_ms.jsp. Accessed April 13, 2010. - Who gets MS? Multiple Sclerosis Association of America Web Site. http://www.msassociation.org/about_multiple_sclerosis/whogets/. Accessed April 13, 2010.
- Epidemiology of MS. National Multiple Sclerosis Society Web Site. http://www.nationalmssociety.org/about-multiple-sclerosis/who-gets-ms/epidemiology-of-ms/index.aspx. Accessed April 13, 2010.
- Who Gets MS? National Multiple Sclerosis Society Web Site. http://www.nationalmssociety.org/about-multiple-sclerosis/who-gets-ms?index.aspx. Accessed April 13, 2010.
- What causes MS? National Multiple Sclerosis Society Web Site. http://www.nationalmssociety.org/about-multiple-sclerosis/what-causes-ms/index.aspx. Accessed April 13, 2010.
- Bowling, Allen C, and Stewart, Tom. "So, What's new about Vitamin D?" Inside MS. October-November 2006. www.nationalmssociety.org/download.aspx?id=133.
