Multiple sclerosis risk factors: who is more likely to get MS

What multiple sclerosis is

MS is a long-lasting disease of the brain and spinal cord. It damages myelin, the protective coating around nerve fibers that helps nerves send messages quickly. When myelin is damaged, messages between the brain and body slow down or get blocked, and that causes MS symptoms (MedlinePlus).

No one knows the exact cause. Many experts believe MS is an autoimmune disease, meaning the immune system mistakenly attacks healthy cells (MedlinePlus). MS affects people differently: some have mild symptoms with little disability, others get worse over time. Most people with MS have a normal life expectancy (NINDS).

Risk factors

MedlinePlus says several factors may work together to raise the risk of MS (MedlinePlus). NINDS gives more detail on each (NINDS):

• Age. MS most often begins between ages 20 and 40 (MedlinePlus).
• Sex. MS is two to three times more common in women than in men (MedlinePlus).
• Family history and genes. Having a parent or sibling with MS raises the chance of getting it, although MS itself is not an inherited disorder. Research suggests hundreds of gene variants combine to create vulnerability, and most of the known ones relate to the immune system (NINDS).
• Epstein-Barr virus (EBV). EBV, which causes mononucleosis (mono), is the virus most consistently linked to MS. Almost everyone has had EBV at some point; the few who have not are at lower risk. Getting EBV in childhood carries a lower risk than getting it as a teen or adult, and the vast majority of people with EBV never get MS (NINDS).
• Little sun and low vitamin D. People who spend more time in the sun, or have relatively higher vitamin D levels, are less likely to develop MS. People from regions near the equator generally have a much lower risk than people from temperate areas such as the U.S. and Canada (NINDS).
• Smoking. People who smoke are more likely to develop MS and to have a more aggressive course (NINDS).
• Race and ethnicity. People of all races and ethnicities can get MS, but it is most common in White people (NINDS).

If you smoke, the quit smoking help check covers the help available to quit.

Early signs to bring to a doctor

Early MS symptoms often include (NINDS):

• vision problems, such as double vision or optic neuritis (inflammation of the optic nerve), which causes pain with eye movement and vision loss
• muscle weakness, often in the arms and legs, and stiffness with painful spasms
• tingling, numbness or pain in the arms, legs, trunk or face
• clumsiness, especially trouble staying balanced when walking
• bladder control problems
• dizziness that comes and goes or is constant

MS can also cause fatigue, mood changes such as depression, and problems with thinking and memory (NINDS). Many people with MS find their symptoms are worse with a fever or in heat (NINDS). In most cases doctors diagnose MS from the symptoms and typical signs on an MRI scan (NINDS).

Common questions

At what age does MS usually start?

Usually between 20 and 40 (NINDS) (MedlinePlus). That makes MS different from many conditions on this site, where risk rises with older age.

Is MS hereditary?

Not directly. NINDS says MS is not an inherited disorder, but having a parent or sibling with MS raises your chance of getting it (NINDS).

Which risk factors can I change?

Smoking can be changed. Age, sex, genes and a past EBV infection cannot (NINDS). Neither source says that taking vitamin D prevents MS; NINDS describes the link between sun, vitamin D and lower MS risk as what research indicates (NINDS).

Is there a cure?

No, but treatments can reduce the number and severity of relapses and delay long-term progression (NINDS).

Also see Parkinson's disease risk factors, rheumatoid arthritis risk factors, lupus risk factors and screening tests by age.