The EPDA (European Parkinson's Disease Association) worked with WHO (World Health Organization) and came up with a figur e of 6.3 million globally.
(see the Parkinson's Global Declaration )
http://www.epda.eu.com/globalDeclaration/default.asp
The more conservative U.S. says (but has nothing to back it up) that there are either "over a million" or 1.5 million and 4 million worldwide. PAN is working on a bill to work with the MS org to create a mandatory registry. The Ali Center in Arizonia attempted to count heads a while back through a survey, but it failed miserably.
I believe we will have to start somewhere at a point in time and make doctors report to the CDC or somewhere as patients are diagnosed to get a reliable, valid number (which could take forever)! Or maybe this could be done through counting prescriptions filled for PD meds, which would require doctors to put a diagnosis on every Rx written. When it is filled, the pharmacist would send in the count for each dx. I give the responsibility to pharmacists because doctors are already way too busy to see t he significance of doing this. They have to write down a dx for insurance anyway.
I don't know, but this again seems to have slipped through the cracks. I think it is because so many fingers are in the pie (too many orgs), which fractures our direction.
Peggy