An estimated 2,500,000 people in the world have multiple sclerosis. Research suggests the proportion of women with MS is increasing and that roughly between two and three women have MS for every man with the condition.
The distribution of MS around the world is uneven. Generally, the prevalence increases as you travel further north or south from the equator. Those parts of Asia, Africa and America that lie on the equator have extremely low levels of MS, whilst Canada and Scotland have particularly high rates.
Epidemiology: the study of the geographical distribution of a condition and patterns of disease as it affects groups of people
Prevalence: the number of people with a condition. Usually measured in cases per 100,000
Incidence: the number of new cases of a condition within a set period of time, usually a year
A simple geographical spread is not the whole picture. Studies show that certain ethnic groups have a markedly lower prevalence of multiple sclerosis, despite living in countries where MS is common. For instance, the Sami or Lapps of northern Scandinavia and the Inuits in Canada have very low rates of MS. A similar pattern is observed amongst the Maoris of New Zealand.
The fact that multiple sclerosis is most prevalent in northern Europe, North America, Australia and New Zealand has led to speculation that it has been carried around the world by European colonists and settlers. It has been suggested that the origins can be traced back to the Vikings who colonised those parts of Northern Europe where MS is most pronounced and that 'Viking genes' can make people particularly susceptible to MS.
It has also been noted that Scotland has a much higher rate of multiple sclerosis than England or Wales and that areas of high MS prevalence around the world have been settled by Scottish immigrants. In Ireland, the north of which was extensively settled by immigrants from Scotland from the 17th century, the rate in Co Wexford in the south was recorded in 2004 as 121 per 100,000 whilst the rate in County Donegal in the north was 185. A study of Northern Ireland found a rate of 168 in 1996.
Although the 'Viking Genes' idea is appealing, it does not explain the whole pattern in terms of who gets MS. In the UK and the US, large studies have shown that people without a Nordic or European heritage also get MS. In one study of 9 million people in a Californian community, Black men and women had as high or higher risk of getting MS as White residents of the same community.
Studies have also shown that Black people and people from ethnic minorities (BAME) with MS often reach disability levels sooner and may have a different disease course to White people with MS, leading to more cognitive problems in people with MS who are Black or from an ethnic minority. This may be because doctors aren't recognising signs of MS in people from BAME groups, or Black and minority ethnic people might be less likely to seek medical help for MS symptoms, and so they are diagnosed and treated once their MS is more advanced.
The growing evidence for racial differences in MS experiences is discussed in our article 'Who gets MS and Why'.
Multiple sclerosis in the UK
A study by McKenzie et al at the University of Dundee estimated the number of people with MS in the UK, based on GP records. This gave a figure of 127,000 people with MS in the UK in 2010. The study also found that the number of people with MS in the UK is growing by around 2.4% per year, due to people with MS living longer.
Concerns were raised that this figure may have included some records where there was an element of doubt about the diagnosis. If these records were excluded, it suggests that there were about 110,000 people with MS in the UK at that point.
In 2020, Public Health England released new MS prevalence data from GP records from 2018. This revealed that the number of adults with MS in the UK has risen to 131,720. Separate figures for childhood MS suggest that around 250 children in the UK have an MS diagnosis.
Prevalence rates vary around the UK. Based on the figure of 130,000 people with MS, it is estimated that the number of people with MS in each nation is:
- England is around 105,450 or 190 per 100,000
- Wales about 5,600 or 179 per 100,000
- Northern Ireland about 4,830 or 258 per 100,000
- Scotland about 15,750 or 290 per 100,000
Prevalence in the north of Scotland is particularly high. A study of north east Scotland found the level per 100,000 people in 2009 to be 229 in Aberdeen, 295 in Shetland and 402 in Orkney.
A little over 6,700 people are diagnosed with MS each year, roughly 130 a week.
Changes over time
There is evidence to suggest that both MS incidence and prevalence rates have increased over the last few decades. Better access to neurology services and better diagnostic criteria mean that more cases of MS are detected than previously. Also, as people now tend to live longer in general and live longer with MS, the prevalence of MS appears to be greater as well.
It is likely that lifestyle factors that have changed over the years will have affected the rates of prevalence and incidence as well. A study of these rates in Norway over the last eighty years suggested that people smoked more and got less vitamin D from being outside than at the start of the study period, and that this could have affected the rate at which people acquired MS.
There are two MS register projects underway in the UK. Signing up with one or both of these (if applicable) means that your experience with MS can help inform and shape future research and health policy. The more information that is known about how many people in the country live with MS and what their needs are, the better our health services can change to meet their needs.
In both cases you can update the register from time to time if you experience changes, and if you wish, your medical data can be linked to your record if you are based with one of the partner hospital trusts. All data collected is anonymised, and researchers can not access any information that identifies you specifically.
- The UK MS Register is a scheme that allows people to upload information about their condition that allows researchers to look at different aspects of the condition across a large number of people. There are almost 15,000 people registered.
- The Scottish MS Register gathers information from records on new diagnoses of MS. This register has been running since 2010. In that time about 430 new cases of MS have been reported each year in Scotland, a lower incidence rate than suggested by the Dundee study.
- London:Churchill Livingstone;2005. McAlpine's multiple sclerosis (4th ed).
- Journal of Neurology Neurosurgery and Psychiatry 2004;75:572–576. Full article (PDF 250KB) Latitudinal variation in the prevalence of multiple sclerosis in Ireland, an effect of genetic diversity.
- Neurological Sciences 2001;22:117-139. Summary The prevalence of multiple sclerosis in the world: an update.
- Lancet Neurology 2006;5(11):932-936. Summary Sex ratio of multiple sclerosis in Canada: a longitudinal study.
- Journal of Neurology 2007;254(12):1736-1741. Summary Incidence of multiple sclerosis in the United Kingdom: findings from a population-based cohort.
- Journal of Neurology, Neurosurgery and Psychiatry 2012;83(7):719-724. Summary A new prevalence study of multiple sclerosis in Orkney, Shetland and Aberdeen city.
- Journal of Neurology, Neurosurgery and Psychiatry 2014;85(1)76-84. Full article Incidence and prevalence of multiple sclerosis in the UK 1990-2010: a descriptive study in the General Practice Research Database.
- MS in the UK - January 2018
- Summary report (pdf 68kb) National Report 2015 - September 2015.
- UK government briefing Multiple Sclerosis: prevalence, incidence and smoking status - data briefing
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Who gets MS and why?
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 succeptible to multiple sclerosis and why that might be.