Prevalence of Multiple Sclerosis
The global prevalence of multiple sclerosis is approximately 35.9 per 100,000 population, with an estimated 2.8 million people living with MS worldwide, though this varies dramatically by geographic region. 1
Global and Regional Prevalence
In the United States, approximately 900,000 people are affected by MS, representing one of the highest prevalence regions globally. 2
High-prevalence regions (North America and Europe) demonstrate rates exceeding 100 per 100,000 inhabitants, while low-prevalence regions (Eastern Asia and sub-Saharan Africa) show rates as low as 2 per 100,000 population. 3
France specifically shows a prevalence of 94.7 per 100,000 population, with higher rates concentrated in the northern and eastern regions of the country. 3
The worldwide prevalence ranges from 5 to 300 per 100,000 people, with a clear latitude gradient showing increasing prevalence at higher latitudes away from the equator. 2
Temporal Trends
MS prevalence has increased in every world region since 2013, suggesting either true increases in disease occurrence or improved diagnostic capabilities and case ascertainment. 1
The incidence of MS is rising worldwide, along with the socioeconomic burden of the disease, though the underlying mechanisms driving this increase remain incompletely understood. 4
The pooled incidence rate across 75 reporting countries is 2.1 per 100,000 persons per year. 1
Demographic Patterns
Females are twice as likely to develop MS as males globally, with the female-to-male ratio approaching 3:1 in recent decades. 2, 1
In France and several other countries, the gender ratio for MS incidence increased from 2:1 to 3:1 between the 1950s and 2000s, but this shift occurred only for the relapsing-remitting form. 3
The mean age of diagnosis is 32 years, with typical presentation occurring in young adults aged 20-30 years. 2, 1
Important Caveats
Significant gaps in prevalence estimates persist across many regions, particularly in low- and middle-income countries where surveillance systems may be inadequate. 1
Prevalence estimates vary considerably based on diagnostic criteria used, case ascertainment methods, and healthcare access, making direct comparisons between studies and time periods challenging. 3
The disease shows ethnic variation, with higher rates in populations of European ancestry and lower rates in Asian and sub-Saharan African populations, though migration studies suggest environmental factors play a substantial role beyond genetics alone. 5, 3