Below find the links to the Nurses Health Study (NHS) and the Health Professionals Follow-up Study (HPFS), which includes documention of individuals with Parkinson's Disease in existing and ongoing cohorts for cancer and other chronic conditions. 

http://www.channing.harvard.edu/nhs/questionnaires/index.shtml

http://www.hsph.harvard.edu/hpfs/hpfs_qx.htm