Dementia in People With Multiple Sclerosis: A Systematic Review and Meta-Analysis
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Updated: Sep 20, 2025
Comprehensive Autopsy Program for Individuals with Multiple Sclerosis
Published on: July 19, 2019
Omid Mirmosayyeb1,2, Danial Dehghani Firouzabadi3, Soroush Oraee4
1Isfahan Neurosciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
Introduction:
Multiple sclerosis (MS), as an autoimmune demyelinating disorder, is associated with cognitive dysfunction. Dementia can result from severe cognitive dysfunction or other pathways in MS, but the exact mechanisms and prevalence are unknown.
Objective:
This review aimed to determine the pooled prevalence and risk of dementia in people with MS (PwMS).
Design:
This meta-analysis was performed in accordance with the guidelines established by the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA).
Methods:
Embase, PubMed, Web of Science, and Scopus were comprehensively searched up to August 29, 2024, to identify observational studies that examined the prevalence or hazard ratio (HR) of dementia among PwMS. This meta-analysis used a random-effects model to calculate the pooled prevalence and risk of dementia among PwMS, where the prevalence rate and HR were the main metrics for effect size.
Results:
Ten studies, including a total of 37,831 PwMS, estimated the prevalence of dementia in PwMS to be 5.31% (I2 = 99.2%, 95% CI: 2.25%-11.98%). In addition, a meta-analysis of four studies assessed the HR of dementia among PwMS, revealing a pooled HR of 1.67 (p < 0.01, I2 = 73.5%, 95% CI: 1.31-2.13).
Conclusion:
While dementia is not a common feature of MS, PwMS still have a significantly higher risk of developing it, compared to healthy indiviuals. However, the considerable variability across studies indicates that these estimates should be interpreted with caution, as inconsistencies in research approaches may have influenced the results. These findings warrant further validation.
Insights
People with multiple sclerosis (MS) have a 1.67 times higher risk of dementia. While not common, the prevalence of dementia in MS is 5.31%, warranting further research.
Area of Science:
- Neurology
- Neuroimmunology
- Cognitive Science
Background:
- Multiple sclerosis (MS) is an autoimmune disorder affecting the central nervous system.
- Cognitive dysfunction is a known complication of MS, with potential links to dementia.
- The precise mechanisms and prevalence of dementia in MS remain unclear.
Purpose of the Study:
- To determine the pooled prevalence of dementia in people with MS (PwMS).
- To assess the pooled risk (hazard ratio) of dementia in PwMS.
- To synthesize existing evidence on dementia in the context of multiple sclerosis.
Main Methods:
- A systematic meta-analysis adhering to PRISMA guidelines.
- Comprehensive literature search across Embase, PubMed, Web of Science, and Scopus databases.
- Inclusion of observational studies reporting dementia prevalence or hazard ratios in PwMS.
- Random-effects model utilized for calculating pooled prevalence and hazard ratios.
Main Results:
- The pooled prevalence of dementia among 37,831 people with MS was 5.31% (95% CI: 2.25%-11.98%).
- A pooled hazard ratio of 1.67 (p < 0.01) indicated a significantly increased risk of dementia in PwMS.
- High heterogeneity (I² > 70%) was observed in both prevalence and risk estimates.
Conclusions:
- Dementia is not a frequent occurrence in MS but PwMS face a substantially elevated risk compared to the general population.
- Significant heterogeneity across studies suggests caution in interpreting pooled estimates.
- Further research is needed to validate these findings and explore underlying mechanisms.
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