Rising prevalence of multiple sclerosis worldwide: Insights from the Atlas of MS, third edition

Abstract

Background: High-quality epidemiologic data worldwide are needed to improve our understanding of disease risk, support health policy to meet the diverse needs of people with multiple sclerosis (MS) and support advocacy efforts.

Objectives: The Atlas of MS is an open-source global compendium of data regarding the epidemiology of MS and the availability of resources for people with MS reported at country, regional and global levels.

Methods: Country representatives reported epidemiologic data and their sources via survey between September 2019 and March 2020, covering prevalence and incidence in males, females and children, and age and MS type at diagnosis. Regional analyses and comparisons with 2013 data were conducted.

Results: A total of 2.8 million people are estimated to live with MS worldwide (35.9 per 100,000 population). MS prevalence has increased in every world region since 2013 but gaps in prevalence estimates persist. The pooled incidence rate across 75 reporting countries is 2.1 per 100,000 persons/year, and the mean age of diagnosis is 32 years. Females are twice as likely to live with MS as males.

Conclusions: The global prevalence of MS has risen since 2013, but good surveillance data is not universal. Action is needed by multiple stakeholders to close knowledge gaps.

Keywords: Multiple sclerosis; epidemiology.

Figure 1.

Map showing geographic variation in MS prevalence and in data confidence scores^a by country: (a) MS prevalence per 100,000 population by country shown in shades of orange and red as per the key. Countries without prevalence data are shown in grey. (b) Confidence score assigned to each country based on the prevalence data sources provided. Scores of very low, low, moderate or high are shown in shades of orange and red as per the key. Countries without prevalence data or with data but no source information provided are shown in grey. ^aCountry confidence scores were assigned using four variables: (1) size of the population covered by data source, from 0 if unknown to 5 if covering the whole country; (2) year of data collection by source, from 0 if prior to 2009 to 5 if in 2017–2019; (3) type of data source, from 0 if unknown to 5 if peer-reviewed journal publication; (4) additional points were given for meeting certain methodological criteria: using the 2017 McDonald Criteria, performing a validation step or using multiple consistent data sources for the estimate. Confidence ratings were assigned based on the total scores using the following thresholds: ⩽5 = very low, 6–10 = low, 11–15 = moderate, ⩾16 = high.