Pesticides and parkinsonism: is there an etiological link?

Two hundred years ago, Parkinson's disease was rare. Now, it is the second most common neurodegenerative disorder. A recent twin study showed clearly that genetic factors play a minor role in determining whether an individual develops this disease, rekindling an interest in the etiological significance of environmental factors. Earlier studies had shown that a MPTP, a contaminant found in some illegal drugs, caused Parkinson's disease. This provided the original impetus for the pesticide hypothesis. Similarities between MPTP and pesticides coupled with epidemiological and animal studies have strengthened the possible link between pesticide exposure and the subsequent development of Parkinson's disease.