PARIS — The European Academy of Neurology Congress in 2026 will feature new research indicating a rise in the prevalence of multiple sclerosis and motor neuron disease. This increase is linked to improved life expectancy among patients and aging populations, according to health data collected from France and Sweden.

Researchers examined trends in prevalence, incidence, and life expectancy for Parkinson's disease, multiple sclerosis, and motor neuron disease between 2003 and 2022. They analyzed nationwide health data from the entire populations of both France and Sweden. The number of individuals living with Parkinson's disease, multiple sclerosis, and motor neuron disease increased during this period.

Multiple sclerosis prevalence increased largely because patients are living longer after diagnosis. Life expectancy also improved for people living with both multiple sclerosis and motor neuron disease. Crude incidence for Parkinson's disease and multiple sclerosis remained stable from 2003 to 2022. However, both crude and age-adjusted incidence increased for motor neuron disease during the same timeframe. Life expectancy for people with Parkinson's disease increased between 2003 and 2013 before declining in subsequent years.

"The fastest-growing disease in terms of prevalence is multiple sclerosis. Importantly, this rise does not appear to be driven by increasing incidence, but by improved life expectancy among patients," said Dr. Thomas Nedelec, the lead researcher. Nedelec is affiliated with Sorbonne University and the Paris Brain Institute. "For multiple sclerosis, advances in immunosuppressive and immunomodulatory therapies may have contributed substantially by reducing disease activity and improving long-term outcomes."

Study authors attributed much of the increase in motor neuron disease incidence to population aging, while acknowledging that greater awareness and improved diagnosis might have contributed to more identified cases. The authors also suggested that the decline in new Parkinson's disease cases might reflect better disease management and improved treatment of cardiovascular conditions.

"We see a clear need for a large-scale European initiative that reproduces this type of analysis across the continent. This would help us better understand differences between countries and improve our understanding of the factors driving these diseases," Nedelec said. The research is scheduled for publication in the journal Neurology.

No independent assessment was available for this report.