What causes multiple sclerosis (MS)?

Scientists have learned a great deal about multiple sclerosis (MS) in recent years; still, its cause remains elusive. Many investigators believe MS to be an autoimmune disease -- one in which the body, through its immune system, launches a defensive attack against its own tissues. In the case of MS, it is the nerve-insulating myelin that comes under assault. Such assaults may be linked to an unknown environmental trigger, perhaps a virus.

This answer from the National Institute of Neurological Disorders and Stroke.

Most research still points towards multiple sclerosis (MS) having both genetic and environmental causes. First-degree relatives (brothers, sisters, children, and parents) of a person with MS have a roughly 2.5 percent risk of MS in their lifetime. If one identical twin has MS, there is a one-third chance that the other will as well. These findings are consistent with a genetic contribution of some nature to the risk of MS.

MS is more common as one moves away from the equator, which may be due to various factors. Researchers propose that exposure to common viruses before age 15 may play a role in fooling the immune system and lead to an autoimmune disease like MS. These viruses may be more commonly encountered as we move away from the equator. Research has also suggested that low levels of vitamin D may be associated with a higher MS risk. Due to less sunlight exposure, vitamin D levels tend to be lower as we get further from the equator.

Several studies have shown that the majority of people with multiple sclerosis (MS) have low levels of vitamin D (as measured by 25 hydroxy vitamin D levels in the blood). We know that vitamin D plays an important role in bone health, but its role in the immune system is equally important.

Increased levels of vitamin D are associated with increased numbers of T regulatory cells. These cells may help dampen the immune over-activity seen in disorders like MS. Vitamin D is obtained both through diet and sunlight exposure. Correcting Vitamin D deficiencies in people with MS may make a difference. A small study at the University of Toronto demonstrated fewer relapses in people with MS treated with oral Vitamin D.

No one knows what actually causes multiple sclerosis (MS), but we do know that it is an acquired disease - you are not born with it. Multiple sclerosis is also an exogenous disease, meaning that it is contracted from the outside. And fortunately, it is not contagious. American researchers have shown that the rate of increased prevalence among husbands and wives is only 1 percent. In England, the prevalence of MS among husbands and wives is less than among the general population, occurring at a rate of 4.9 per 10,000 compared with 5.0 per 10,000.

The cause of multiple sclerosis (MS) remains to be identified conclusively. It is thought that MS is an autoimmune disease, that is, a disease where the immune system attacks body tissues as if they were foreign proteins. What triggers this process in initiating or exacerbating MS is unknown.

The cause of multiple sclerosis (MS) is unknown. Because a person's risk of MS is slightly higher in some families when a relative has MS, there may be a genetic link.

The cause of multiple sclerosis (MS) is unknown. Because a person's risk of MS is slightly higher in some families when a relative has MS, there may be a genetic link.

Some research suggests that where you lived as a child and viral illnesses you have had could be triggers for MS later in life. But these links have not been proved.