The number of people living with Parkinson's disease, multiple sclerosis, and motor neuron disease is increasing due to different underlying factors, according to research presented at the European Academy of Neurology Congress 2026 and published in Neurology on June 15.
Researchers from France and Sweden analyzed nationwide health data from both countries between 2003 and 2022 to examine trends in prevalence, incidence, and life expectancy for these neurological conditions. The study found that while the overall number of people affected by all three diseases has grown, the reasons for this increase vary between each condition.
For multiple sclerosis (MS), prevalence appears to be rising mainly because patients are living longer after diagnosis. Lead author Dr. Thomas Nedelec from Sorbonne University and the Paris Brain Institute said, "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." He added that advances in immunosuppressive and immunomodulatory therapies may have played a substantial role: "For multiple sclerosis, advances in immunosuppressive and immunomodulatory therapies may have contributed substantially by reducing disease activity and improving long-term outcomes."
In contrast, motor neuron disease (MND) was the only condition studied that showed an increase in age-adjusted incidence over time. Researchers said population ageing explains much of this rise but noted other contributing factors such as greater awareness or improvements in diagnosis could also play a role. They did not rule out changing environmental or lifestyle-related risk factors.
For Parkinson's disease (PD), age-adjusted incidence declined during the study period despite historical increases in overall prevalence—suggesting improved survival rather than increased risk accounts for more cases today. The researchers indicated that better management of PD itself as well as related health conditions like cardiovascular disease may explain these trends.
The authors highlighted that understanding whether rising numbers are due to increased survival or higher incidence has significant implications for healthcare planning and prevention strategies moving forward. Dr. Nedelec concluded: "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."
