October 31, 2026

@michaelokun

Is the Parkinson's pandemic growing, or are we confusing more cases w/ more risk? Incidence refers to the number of new cases of a disease developing over a specific period. Prevalence refers to the total number of folks living w/ that disease. These are two very different measures, and understanding the difference matters. Daniele Urso and colleagues describe in a new viewpoint paper in Movement Disorders why the worldwide burden of Parkinson's disease continues to grow, even though the risk of developing Parkinson's may not be increasing in many countries. Key points: - Population-based studies from several countries suggest that age-adjusted Parkinson's incidence has remained stable or declined, despite a growing number of folks living w/ the disease. - Population aging, longer survival and improved recognition of Parkinson's can increase prevalence even when the underlying risk of developing the disease remains unchanged. - Most available incidence studies come from high-income countries, leaving major gaps in our understanding of trends in low- and middle-income countries, where approximately 85% of the world's population lives. My take: This is an important and provocative paper, particularly because I was one of the authors who helped introduce the concept of the Parkinson pandemic. What resonates w/ me is that we must distinguish the growing number of folks living w/ Parkinson's from the changing risk of developing it. Both matter, however they answer different questions. The authors are correct to challenge us to improve our measurements. I would caution against interpreting these findings as evidence that environmental risks are disappearing or that prevention is becoming less urgent. Pesticides, solvents, air pollution and other potentially modifiable exposures remain important areas of investigation. The absence of a consistent increase in age-adjusted incidence in selected countries does not mean we have solved the Parkinson's problem. It means we need better data, particularly from countries that have historically been underrepresented. The decline or leveling in some European countries is important given they have been aggressive in banning.