Parkinson's disease and pesticide exposures.

INTRODUCTION

Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder in which loss of dopaminergic neurons in the basal ganglia leads to tremor, bradykinesia, rigidity and postural instability.

METHODS

Literature search using Medline with keywords 'Parkinson's disease' and 'pesticides', limited to English, was undertaken, supplemented by articles from the author's files.

RESULTS

Many studies have found an association between pesticides and PD, but no one agent has been consistently identified. Those implicated include organochlorine insecticides, maneb and paraquat. One meta-analysis of pesticide exposure and PD found an almost doubling of risk in those exposed. Associations with specific agents may be confounded by exposure to other pesticides, making it difficult to identify the causative agent.

CONCLUSIONS

The available evidence indicates that pesticides are associated with PD, but further research is needed to identify long-term biomarkers of exposure, improve methods for estimating pesticide-exposure and undertake prospective cohort studies of pesticide-exposed workers.