|FACTS AND FIGURES |
Epidemiology of Parkinson Disease
The "prevalence" of a disease can be defined as the number of cases of a specific disease present in a given population at a certain time. The National Parkinson Foundation (NPF) website provides general estimates of the prevalence of Parkinson disease: approximately one million people currently have PD in the United States.1 Each year, NPF estimates that 50,000 to 60,000 new cases of PD are diagnosed.
However, research studies examining PD prevalence report rates that vary widely. This is because prevalence studies often use different research methods to make their estimates. In 2006, De Lau and Breteler2 reviewed the PD epidemiology literature and reported a prevalence rate of approximately 1% in persons 60 and older. Studies with the highest rates reported prevalence up to 4%.
Recently, Wright Willis and colleagues3 expanded our understanding of epidemiological aspects of PD by studying geographic and ethnic variation of PD in a population-based study of US Medicare beneficiaries. Results suggested that the mean prevalence of PD among persons 65 and older was 1.6%. The prevalence of PD in Blacks and Asians was about 50% lower than that in whites.
Interestingly, statistical analyses of zip codes in which lived persons with PD showed nonrandom distributions of PD across counties within states in the US. Rates were substantially higher in the Midwest/Great Lakes Region and the Northeastern Seaboard when compared to other parts of the country.3 One hypothesis to explain this finding is that this higher prevalence is the result of industrial exposures which, presumably, are higher in these geographic regions (i.e., the “rust belt” and industrial Northeast).
There are far fewer studies examining the prevalence of young-onset Parkinson disease (YOPD). Many researchers consider the age range for having YOPD as when a diagnosis is given between 21 and 40 years. In their review of YOPD, Schrag and colleagues4 cited studies that reported the occurrence of YOPD in approximately 1 out of 100,000 persons; i.e., it is a rare condition.
Prepared by Thomas Fritsch, Ph.D.
1. National Parkinson Foundation. (1) National Parkinson Foundation. Parkinson Disease Overview 2012.
Available at http://www.parkinson.org/parkinson-s-disease.aspx. Accessed 3/2/2012.
2. De Lau LLL Epidemiology of Parkinson’s disease. Lancet Neurol 2006;5:525-535.
3. Wright Willis A, Evanoff BA, Lian M, et al. Geographic and ethnic variation in Parkinson disease:
A population-based study of US Medicare beneficiaries. Neuroepidemiology 2010;34:143-151.
4. Schrag A, Ben-Schlomo Y, Brown R, Marsden CD, Quinn N. Young-onset Parkinson’s disease revisited:
Clinical features, natural history, and mortality. Mov Disord 1998;13:885-894.