Objectives The objective of this study was to assess the risk of occupational exposure to pesticides on the development of Parkinson Disease.

Methods We conducted a multi-centre hospital-based case-control study in the Netherlands. All patients, diagnosed with Parkinson Disease in one of the five participating hospitals between January 2006 and December 2011 were invited to participate. Two age and sex matched controls per patient were recruited from individuals who were seen at the same department of neurology for non-neurodegenerative disorders. The participants were interviewed in a standardised telephone-interview. The questionnaire contained a complete occupational and residential history, and specific questions about potential risk and protective factors for Parkinson Disease. Among those were detailed questions about use of pesticide at work.

Results In total 444 Parkinson Disease patients and 876 controls were included in the analyses. We applied the ALOHA Job-Exposure-Matrix to assess exposure to pesticides in general and specifically to insecticides, to herbicides and to fungicides. Self-reported information allowed for a more detailed categorization of application and re-entry exposure. Preliminary analyses of the data show a slightly increased risk for Parkinson Disease for active application of herbicides and insecticides.

Conclusions Our results confirm earlier studies showing an elevated risk for Parkinson Disease after exposure to herbicides and insecticides. The final analyses will show the results of different levels of cumulative exposure resulting from application and re-entry exposure.