Causes of Multiple Sclerosis
Although a lot of research has been done, scientists have not yet found the exact cause of multiple sclerosis, but current research does lean toward some possible factors. These factors may cause a risk for developing MS under some conditions that have not been discovered yet. Multiple sclerosis is not contagious whatsoever and is not inherited, however the MS Society of Canada and its Scientific Research Foundation emphasize the research on MS due to its genetic involvement.
Immunologic Factors
As mentioned before, generally in MS, the immune system has an abnormal response that aims against the myelin sheath on the nerve fibres in the central nervous system. This is called an autoimmune process. The myelin sheath sometimes mutates in one's nerve tissue and when the immune system goes across it, it does not recognize the myelin in its mutated form and attacks it. Today, the exact structure of the mutated myelin, or the antigen, that the immune system tends to attack is still unknown. However, in the recent years, scientists have been able to identify some on the problems. For example, they have been able to identify which immune cells are involved in the attack, some of the factors that causes them to attack, some of the sites or receptors on the attacking cells that are attracted to the myelin to initiate the attack. Today scientists are working hard to learn about the autoimmune process in multiple sclerosis. They are focusing on what starts it, how it works, and also how to slow it down or stop it completely.
Environmental Factors
Epidemiologists, scientists who study disease patterns, look at many factors that help understand why these patterns exist. These include patterns in geographical locations, demographic differences, genetics, and many more.
It has been discovered that MS occurs more often in some countries versus others. Caucasians, particularly in North America, Europe, and Australia, are most commonly affected by MS. Research has also shown that multiple sclerosis occurs more commonly in countries farther away from the equator.The reason may be lack of vitamin D. The human body produces vitamin D naturally when the skin is exposed to sunlight. People who live near the equator tend to have higher levels of naturally-produced vitamin D since they receive great amounts of sunlight year-round. Vitamin D is though to be beneficial because it prevents diseases like MS by acting on the immune system.
Some research proves that there is a possible connection between the location a person has lived for the first 15 years of their life and the incidence of MS. This means that if a 15-year-old child who moves to an area where there is a higher or lower risk of MS develops the same probability of getting MS as the people who have always lived in that area. People who move that are older than 15 years of age remain just as likely to get MS as the area they used to live in. Studies show that if one gets exposed to some environmental agent before puberty, they may have a chance of developing MS later on.
It has been discovered that MS occurs more often in some countries versus others. Caucasians, particularly in North America, Europe, and Australia, are most commonly affected by MS. Research has also shown that multiple sclerosis occurs more commonly in countries farther away from the equator.The reason may be lack of vitamin D. The human body produces vitamin D naturally when the skin is exposed to sunlight. People who live near the equator tend to have higher levels of naturally-produced vitamin D since they receive great amounts of sunlight year-round. Vitamin D is though to be beneficial because it prevents diseases like MS by acting on the immune system.
Some research proves that there is a possible connection between the location a person has lived for the first 15 years of their life and the incidence of MS. This means that if a 15-year-old child who moves to an area where there is a higher or lower risk of MS develops the same probability of getting MS as the people who have always lived in that area. People who move that are older than 15 years of age remain just as likely to get MS as the area they used to live in. Studies show that if one gets exposed to some environmental agent before puberty, they may have a chance of developing MS later on.
Genetic Factors
The chances of developing MS increase greatly if a family member has MS to start with even though it is not hereditary in a strict sense. Researchers hypothesize that a person can be born with a genetic tendency to MS that reacts to an environmental agent. If the person is exposed to this agent, it can initiate the abnormal response of the autoimmune system. People with family members or close relatives who have MS have a higher chance of developing MS compared to the general population. Research has shown that individuals with a parent or sibling with MS have a 3% chance of developing MS themselves as opposed to 0.02% chance of others.
Infectious Factors
Epstein-Barr Virus
It is often believed that the existence of a virus or an infection can lead to the development of multiple sclerosis. Many viruses and bacteria, such as measles and Epstein-Barr, are being investigated to see whether they contribute towards triggering MS.
Although there has been no direct link found between MS and any particular virus or bacteria or infection, there are some speculations that measles virus and the Epstein-Barr virus, in addition to a few other viruses, have resulted in the existence of MS. A few evidences that link viruses to MS are as follows:
Although there has been no direct link found between MS and any particular virus or bacteria or infection, there are some speculations that measles virus and the Epstein-Barr virus, in addition to a few other viruses, have resulted in the existence of MS. A few evidences that link viruses to MS are as follows:
- Viruses that cause demyelination weaken the nervous system by slowing down the nerve impulses, exposing the body to possible development of MS.
- Epidemiological studies have shown that some viruses are such that they stay in the body and act against it after long periods of time. MS portrays the same characteristics and is thus thought to have links with these types of viruses.
- Epstein-Barr virus (EBV) has also been suggested as a possible culprit. In 2007, a study of the postmortem brains of people with MS revealed traces of EBV in the brains. Out of 22 brains with MS, 21 of them were infiltrated with traces of EBV infection. On the other hand, there was no EBV infection found in brains that had similar inflammations to those with MS.