A meta-analysis was recently carried out in Italy by Emanuele Cereda from the IRCCS University Hospital San Matteo Foundation in Pavia, and Gianni Pezzoli of the Parkinson Institute (ICP) in Milan to compare the results of 104 international studies on the potential toxic effects of exposure to pesticides.

The findings, published on the international scientific journal Neurology of Washington ("Exposure to pesticides or solvents and risk of Parkinson disease") suggest that people exposed to pesticides, weed-killers and solvents had an increased risk of developing Parkinson's disease of between 33% and 80% compared with people who were not exposed.

The researchers report that some studies specifically explored how the home or work environment affected disease risk and that exposure either to the weed killer "paraquat" or the fungicides "maneb" and "mancozeb" appeared to double the risk for Parkinson's.

The authors of the report call for further prospective and high-quality case-control studies to prove whether these chemicals actually increase the risk of developing Parkinson's disease. The report also suggests that further studies should concentrate on specific chemicals.

Although the study did not investigate whether the type of exposure, such as whether the compound was inhaled or absorbed through the skin, and the method of application, such as spraying or mixing, affects risk, the researchers pointed out that their analysis is useful for planning new preventive health policies.

This report is the first Italian report to show that there is a relationship between insecticides and herbicides as well as other solvent chemicals to which many people are exposed and the development of Parkinson’s disease. When looking at the developments in France which has recognised Parkinson's as being a pesticide-related illness, this is worrying.