10 Multiple Sclerosis Risk Factors

Many mysteries remain about who gets multiple sclerosis (MS), but this much is clear: Both genes and environment seem to play a role.

Multiple sclerosis is a disease with nuances surrounding it that continue to baffle experts. But, according to Johns Hopkins Medicine, we know MS is an autoimmune disease that occurs when the body attacks its central nervous system. This process causes damaging inflammation that interrupts the way the nervous system communicates with the rest of the body, leading to various symptoms.

Here are ten risk factors that may increase your chances of developing MS:


Montel Williams and a few other high-profile male celebrities have been diagnosed with MS, but by and large, MS disproportionately strikes women, Nancy L. Sicotte, MD, said. And the gender gap is growing: "It used to be two women to every one man, but several new studies suggest that the ratio is approaching 4-to-1," Dr. Sicotte said.

In addition, even though the disease is more common among females (they are also more likely to get MS at a younger age), it tends to be more severe in men, John Rose, MD, professor of neurology at the University of Utah, said.

Where You Live

According to a review study published in 2019 in the journal Annals of Clinical and Translational Neurology, the prevalence of people diagnosed with MS increases the farther away you are from the equator. It is thought that vitamin D, or lack thereof, is the reason. Our bodies produce D in response to sunlight, so people farther from the equator make less, especially during the long, dark winter months.

RELATED: My Doctor Dismissed My MS Symptoms as 'Stress'—Even Though My Body Was Going Numb

Environmental Exposures as a Child

According to the same review study published in 2019 in the journal Annals of Clinical and Translational Neurology, environmental exposures associated with the development of MS may occur before the age of 15 years. This is based on studies on migration.

The same study also mentions exposures to maternal illness while in utero (other than diabetes and preeclampsia) and environmental exposures to the neonate (young infant), such as lower levels of vitamin D, that are thought to possibly play a role in the development of MS.

When You Were Born

A study published in 2016 in the journal JAMA Neurology examined the month of birth and subsequent diagnosis of MS among birth data in the UK (England, Wales, and Scotland) between 1938-2000. The authors controlled for other variables and found an increased risk of developing MS among persons born in April. Conversely, of those born in November, 15.58% fewer individuals developed MS.

A possible explanation: "If your mother was pregnant with you through the winter, her levels of vitamin D during pregnancy might have been low," Dr. Rose said.

Your Ethnicity

According to a study published in 2020 in the journal Multiple Sclerosis, white individuals of European ancestry are most likely to develop MS. Hispanic, and Asian individuals are less likely to develop the disease.

While populations in northern latitudes generally have higher disease rates, according to the study, variabilities in what have been considered higher-risk populations are changing. For example, there are currently increasing rates of MS in African Americans. Additionally, the study explains there have been increasing reports of Hispanic children diagnosed with MS.

Your Smoking Status

According to a study published in 2019 in the journal Annals of Clinical and Translational Neurology, smoking cigarettes is a well-known risk factor for developing MS. The thought is that the lung irritation and inflammation caused by smoking are the culprits.

However, the good news, according to the study, is that if you quit smoking, after ten years of not smoking cigarettes, your risk returns to your baseline risk. This means that smoking is one of the few modifiable risk factors you can alter to reduce your risk of developing MS.

Your Age

According to Johns Hopkins All Children's Hospital, you can be diagnosed with MS at almost any time, from childhood up to your years as a senior citizen. However, a diagnosis is most likely between the ages of 20 to 50 years old.

"MS is not an all-comers' disease," Carrie Lyn Sammarco, DrNP, FNP-C, MSCN, said. "We don't tend to see it in children, although it can occur." Johns Hopkins All Children's Hospital explained that while uncommon, approximately 5% of MS diagnoses each year are in children.

Previous Mono Infection

Many germs have been studied as possible MS triggers, but the results have been mixed. There is, however, a growing body of evidence that Epstein-Barr virus (EBV) is correlated with subsequent MS diagnosis. EBV is the virus that causes mononculeosis, or mono.

A study published in May 2020 in the Journal of Neurology, Neurosurgery, and Psychiatry collected blood samples from a sample size of 901 patients with an early MS diagnosis from the German National MS Cohort. Every participant tested positive for EBV antibodies. The authors discuss the possibility of MS being a late-stage complication of EBV, with further research indicated.

You Have Another Autoimmune Condition

Triggers that may impact an individual's genetic risk for developing MS are an ongoing area of research. One study, published in 2019 in the journal Annals of Clinical and Translational Neurology, discussed how past infections with Epstein-Barr virus, and other viruses, may affect the development of autoimmune diseases, such as MS, through their effect on genetic expression.

"Genes seem to haywire the autoimmune system," Dr. Rose said.

Your Family History

While environmental factors impact your chances of developing this disease, so do genetics. "If a mom or dad has MS, their children have between a 5 and 10 percent chance of getting it," Dr. Rose said.

Overall, there are many possible risk factors for developing MS, but it is clear it is a complex process. Very few risk factors are clear cut, and variability exists depending on the research behind them. If you are concerned you may have MS or are concerned about your own personal risk factors for MS, your healthcare provider is a great place to start to determine if next steps are needed.

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