Multiple Sclerosis Associated With Higher Risk for Dementia

Multiple sclerosis (MS) is associated with increased risk for dementia, according to study results presented at the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) Congress 2025, held in Barcelona, Spain from September 24 to 26, 2025.

Life expectancy for people with MS has increased due to advances in therapy, but current treatments do not mitigate the neurodegeneration that can contribute to cognitive decline.

Researchers used UK Biobank data (N=500,742; mean [SD] age, 56.5 [8.09]; women, 54.4%) to assess whether MS is associated with dementia risk. The researchers analyzed data from 2520 patients with MS, compared with data from 12,600 matched controls. Cox regression and a Fine-Gray model were used for statistical analysis.

When adjusted for sex, MS was associated with increased risk for dementia (cause-specific hazard ratio [csHR], 2.16; 95% CI, 1.71-2.73). Additional adjustment for education and socioeconomic status did not mitigate the association between MS and dementia.

In the matched cohort, MS remained associated with increased risk for dementia, though the rate of dementia was lower (csHR, 1.79; 95% CI, 1.17-2.74). Additionally, using death as a competing risk, MS remained associated with a greater risk of developing dementia (subdistribution HR, 1.93; 95% CI, 1.47-2.54).

The study authors concluded, “When accounting for the competing risk of death, the relative risk of dementia associated with MS appeared slightly stronger, suggesting that individuals with MS who survive long enough remain at an elevated risk of dementia compared to their matched counterparts.”