Multiple Sclerosis: What causes it?
MS is an autoimmune disease. Doctors still don't understand what causes MS, but there is interesting data that suggests that genetics, a person's environment and possibly even bacteria and viruses may play a role.
How does the environment affect a person's risk of MS?
Epidemiological data show several interesting trends: Different populations and ethnic groups have a markedly different prevalence of MS. The disease is especially common in Scotland, Scandinavia and throughout northern Europe. In the US the prevalence of MS is higher in whites than in other racial groups.
Studies show that MS is more common in certain parts of the world, but if you move from an area with higher risk to one of lower risk, you acquire the risk of your new home if the move occurs prior to adolescence. Such data suggests that exposure to some environmental agent encountered before puberty may predispose a person to MS.
Moreover, MS is a disease of temperate climates. In both hemispheres, its prevalence increases with distance from the equator.
Also there have been reported ‘epidemics’ of MS - for example, the group of people living off the coast of Denmark after WWII, suggesting an environmental cause.
What role do genetics play in MS?
Researchers believe that MS may be inherited (passed on from parents to children). First, second and third degree relatives of people with MS are at increased risk of developing the disease. Siblings of an affected person have about a 2% risk of developing MS.
Researchers believe that there is more than one gene that makes a person more likely to get MS. Some scientists theorise that MS develops because a person is born with a genetic predisposition to react to some environmental agent, which, upon exposure, triggers an autoimmune response.
Sophisticated new techniques for identifying genes may help answer questions about the role of genetics in the development of MS.
Multiple sclerosis in children
Although MS is more common in adults between the ages of 20 and 50, it can affect children and teenagers. It is quite rare for this to happen, but nevertheless as many as five to ten per cent of young people with MS develop the condition before the age of 16. This adds up to more than 4,000 children with MS in the UK.
Children with MS generally experience the same types of symptoms as adults, including cognitive difficulties that can interfere with school performance.
Most medicine used to treat MS in adults is also used in children. However, the effectiveness and safety of these drugs in children and adolescents has not been confirmed.
What viruses are linked to MS?
Some studies have suggested that many viruses such as measles, herpes and the flu viruses may be associated with MS. To date, however, this belief has not been proven.
Are there other potential factors that cause MS?
Some research has suggested that a lack of vitamin D may increase the risk of MS. Although it has been suggested that taking vitamin D supplements may lessen the risk of MS this idea has not be proven.