Who gets MS and why?

16 May 2021

The number of people being diagnosed with multiple sclerosis around the world is increasing. In this article we take a look at recent research which investigates who might be more susceptible to multiple sclerosis and why that might be. 

Around the world, MS diagnoses are on the increase. Multiple sclerosis is most common in Northern Europe, North America, Australia and New Zealand. These countries have majority populations of Nordic and European heritage, leading to suggestions that there is a link between MS  prevalence and 'Viking genes'. However, these countries share other factors, such as similar diets, lifestyle, obesity rates and industrialisation. Countries in the Middle East and South Asia have reported rising MS prevalence alongside increasing adoption of 'Western lifestyles', and there are  similar demyelinating conditions that are common in East Asia and South America. 

It's easy to forget that genetic diversity in humans doesn't just mean skin colour. Most genetic diversity is not something you can see when you look at a person - it's the highly variable pattern of proteins on the surface of your cells, known as your haplotype. Researchers have identified dozens of haplotypes that are associated with a higher risk of developing MS. Many of these are more common in Europe and Scandinavia than elsewhere, but they are not restricted to people of European or Scandinavian ethnicity. 

Of course, genetic susceptibility is only part of the picture. Most people with susceptible haplotypes never develop MS. Researchers think that there is likely to be a trigger that sets off the chain of events in your body that leads to multiple sclerosis. The most likely triggers are some kind of environmental factor, like your diet, smoking, vitamin D levels, viral infection or local air quality.

For environmental triggers, your personal risk is based on where you grew up, not your ethnicity. People who move between countries as adults retain the risk profile of the place they lived as children. Their children and grandchildren take the risk profile of the place that they grow up,  irrespective of their ethnic heritage. So, if there is a link between MS and countries with 'Western' lifestyles, then it is shared by everyone who lives there, whatever their ethnic heritage. 

Does MS affect ethnic groups differently?

Researchers have been concerned for some time that MS affects people differently, which might lead to inequalities of health care. A recent study in London showed that there was a higher prevalence and incidence of MS in White people than Black and South Asian people. However, once diagnosed, other studies have shown that Black people in both the UK and US are likely to notice their MS progress faster and become more disabled at a younger age than White people. 

The Marmot Review published last year reported on the impact of social inequality on health in the last  decade. As the report makes clear ‘Inequalities in health arise because of inequalities in society – in the conditions in which people are born, grow, live, work and age’. Social inequalities can affect people’s trust and engagement with medicine, and the quality of the care they get. We have seen this during the pandemic where people from some ethnic groups have been more at risk of severe disease, but also less likely to receive vaccines. A lack of awareness of MS within some ethnic groups, coupled with delays in seeking medical advice or delays in referral to specialists could result in a delay in diagnosis. This may explain the worse outcomes for Black people with MS – they are further along their MS journey when they reach the neurologist.

Different MS symptoms are more common in different groups of people too. Cognition problems are seen more often in Black people with MS than other people with MS. Although rates of optic neuritis are similar in Black and White people with MS, for Black people it tends to be more severe and cause greater visual disability. And then there is the overall impact of MS on employment and everyday life. Unemployment rates in the US are higher in Black people with MS than in White people with MS. People in some ethnic groups, both here and in the US, may be more likely to be employed in physically demanding jobs such as hospitality, health, or social care. As a result, if they are affected by disability in MS, they are more likely to have to retire or leave work. Someone who is able to pay for exercise classes, and can afford additional medicines and healthy food is  less likely to experience disability progression in MS. Where people have a reduced income due to unemployment, this has a direct impact on how well they can live with MS. Although financial inequality can affect everyone, people from Black and other ethnic groups may be more likely to be pushed into poverty by MS.

Should MS be treated differently in different ethnic groups?

A recent study from the US found that Black people with MS were more likely to have adverse reactions to beta interferon DMDs, and they were less likely to do well on tablet based DMDs. The same study showed that White people tend to find that glatiramer acetate is less effective for them than it is for Black or Asian people. MS is an unpredictable condition. When you and your neurologist discuss the best disease modifying drug (DMD) for you, you are both trying to balance the risks of the DMD against the risk of you experiencing severe MS related disability. 'Watch and wait' has been a fairly common approach to MS treatment in the past, but if your ethnicity means you are more likely to progress faster, then you might prefer to move to more effective treatment options sooner.

What next?

MS affects everyone differently, making it harder to spot these trends. However, the good news is that researchers are now looking directly at health inequality among people with MS across the UK, aiming to ensure that everyone gets the health services and support that they need. The aim is to ensure that every health professional working in MS understands the impact of inequality in MS and how to combat it. We are doing our part to shine a light on inequalities in MS care, and to ensure that the voices of all people with MS are  heard.

Trishna, a person living with MS says:

"There are lots of factors that can influence someone’s overall chances of better outcomes following a diagnosis of MS and we can’t ignore that someone’s ethnicity might be one of them. Whether that’s because of genetics, cultural influences that can make it harder to manage the disease,  and/or socio-economic factors that are more prevalent in certain ethnic groups. As a British Asian living with MS, I think it’s really important that research is being conducted so we can unpick these various threads and optimise personalised and holistic support for everyone living with the  condition. One of the questions I asked when I was diagnosed was simply “How many other Asians in the UK live with MS”? Nobody could tell me. Even now there is limited data available. Let’s continue this conversation so we can find out the answers!"

Find out more

Amezcua, L and McCauley, JL
Race and ethnicity on MS presentation and disease course
Multiple Sclerosis Journal Volume: 26 issue: 5, page(s): 561-567
Link to article (link is external)
Stuifbergen, A, et al
Experiences of African American Women with multiple sclerosis
Int J MS Care (2021) 23 (2): 59–65.
Link to article (link is external)
Albor C, et al.
Ethnicity and prevalence of multiple sclerosis in East London.
Multiple Sclerosis 2017;23(1): 36-42.
Link to article (link is external)
Romanelli RJ, et al.
Multiple sclerosis in a multi-ethnic population from Northern California: a retrospective analysis.
BMC Neurology 2020;20:163.
Link to article (link is external)
Professor Sir Michael Marmot, et al.
The Marmot Review 10 Years On.
Institute of Health Inequity: London; February 2020.
Link to report (link is external)
Harding KH, et al.
Socioeconomic status and disability progression in multiple sclerosis.
Neurology 2019;92(13):e1497-e1506.
Link to article (link is external)