✓ Evidence Based

Multiple Sclerosis Causes: What Causes MS?

Multiple Sclerosis Causes

The cause of Multiple Sclerosis (MS) is still unknown. However, research points to the following MS causes:

  • Genetics
  • Infections
  • Immunologic factors
  • Environmental factors

Multiple Sclerosis Causes

The aim of this article is to discuss how these factors may contribute to the development of MS. Below we look at some of the main causes of MS.

1. Genetics and Multiple Sclerosis

MS is not hereditary. However, genetics are thought to play a role in the development of MS. 

  • Cases of MS have occurred across multiple individuals within the same family. Research has shown that first, second, and third-degree relatives of those diagnosed with this disease are at a much higher risk of developing MS than those who are not. Furthermore, siblings of a person suffering from MS have a 2 to 5% greater risk of developing the disease.
  • Some studies have shown that some genes are higher in populations where the rate of MS is higher.
  • It’s also thought that the development of this condition could be a result of a genetic predisposition to specific environmental agents. When a person with the predisposition comes in contact or is exposed to these environmental agents, this can trigger the development of MS.

2. Infections, Viruses, and Multiple Sclerosis

Exposure to certain viruses, microbes, and bacteria may cause MS. Some types of viruses are associated with the demyelination and inflammation that are characteristic of MS. Therefore, it’s presumed that these viruses could be a triggering factor for the development of MS.

Many viruses have been investigated to determine whether they are involved in MS. These include measles, human herpes virus -6, canine distemper, Epstein-Barr, and Chlamydia pneumonia. While some evidence exists that viruses do play a role in the disease, none have been proven to be the direct cause as of yet.

3. Immunologic Factors and Multiple Sclerosis

The immune system attacks the myelin coating around nerve cells in the central nervous system in those with MS. Researchers have been successful in identifying the immune cells that lead to this particular attack. The factors that cause these cells to attack and their receptors have also been identified.

Extensive research is still being conducted to learn more about the immunologic factors related to MS. This research mainly focuses on the functioning of these cells, how they contribute to the disease, and how to slow down or stop these processes entirely.

4. Environmental Factors and Multiple Sclerosis

Scientists who work on disease patterns, called epidemiologists, are constantly looking at demographics, geography, genetics, and infection variations in an effort to understand how environmental factors play a role. Studies have not found conclusive evidence for environmental factors that trigger MS. However, the existence of MS clusters (where a majority of MS cases occur in specific locations or time periods) points in this direction.

  • MS occurs more frequently in certain areas and climates, such as those located further from the equator.
  • Studies have shown that people who are born in high-risk areas can reduce their risk if they move to areas with a lower risk before the age of 15.
  • Exposure to certain environmental factors prior to puberty period may also increase the risk of developing MS later in life.

Interestingly, Vitamin D may play a role in MS development. It’s been shown that those living closer to the equator have higher levels of Vitamin D because of increased sunlight exposure. Vitamin D supports immune function and can decrease the risk of autoimmune diseases such as MS.


MS is also more common in certain ethnic groups and populations. MS is most common in Scandinavia, Scotland, and Northern Europe.

Smoking increases the likelihood of developing MS. Smoking also increases the severity of symptoms and increases the progression of MS. If a person is suffering from severe MS, quitting smoking may slow down the progression of the disease.

Other Causes of MS

Additional evidence points to other causes of MS, including hormones.

  • Progesterone and estrogen are two female sex hormones that can suppress some immune activity. They reach higher levels when a woman is pregnant, which has been correlated with decreased symptoms of MS.
  • Testosterone can also act to suppress the immune response. High testosterone levels are thought to be one reason why women develop MS more frequently than men.


While the causes of MS are still unknown, it’s likely that several factors are involved in the development of this autoimmune disease. Research is ongoing in many areas, including epidemiology, immunology, and genetics. In order to determine a cure for this disease, researchers need to understand why the disease is developing and the cause of this disease. If they are able to determine the trigger, they may find the way to slow down or completely stop this disease altogether.


To read more about the possible causes of MS, please visit the links below:


Do NOT follow this link or you will be banned from the site!

Evidence Based

This article is based on scientific evidence, and written, fact-checked & medically reviewed by health experts.

Throughout this article, you'll find scientific references (clickable links to highly trusted peer-reviewed scientific papers, links denoted by the numbers in the parentheses (1, 2, 3)).