| Project objectives:
Parkinson's disease and Parkinsonism are similar diseases affecting the central nervous system. The 'Geoparkinson' project(2) is investigating the hypothesis,
supported by clinical and epidemiological data, that occupational exposure to chemicals increases the risk of these diseases, in a genotype-dependent manner.
Using a questionnaire developed within the project, partners are collecting exposure data on 800 patients and 1 600 controls in four countries with different
exposure levels. Laboratories are determining 18 genetic polymorphisms. By contrasting chemical exposure in actual cases and controls, it will be possible
to estimate the risk according to genotype.
Parkinsonís disease (PD) is a degenerative disorder of the central nervous system that often impairs the sufferer's motor skills and speech. It is the
second most common neurodegenerative disease after Alzheimerís disease. There is evidence that both genetic and environmental factors are
important determinants, and a family history of the disease has been shown to be a risk. Different studies have investigated the relationship between
PD and pesticide use. Some of them, but not all, have found an association but to date no specific agent has been implicated consistently and the
degree of pesticide exposure that might result in PD remains unknown.
As a part of the EU-funded research project Geoparkinson, European researchers, have recently investigated the relation between exposure to
solvents, pesticides, iron, copper and manganese and the risk of PD. To this end, the authors undertook a case-control study of 959 prevalent cases
of Parkinsonism (767 with Parkinsonís disease) and 1989 controls in Scotland, Italy, Sweden, Romania, and Malta. Subjects completed an
interviewer-administered questionnaire regarding lifetime occupational and hobby exposure to these substances. Lifetime and average annual
exposures were estimated and statistical analysis was applied. The Geoparkinson project is one of the largest case-control studies to date of genetic,
environmental, and occupational risk factors for Parkinson's disease or other degenerative Parkinsonian syndromes.
The researchers found that Parkinson's disease is associated with pesticide use. Previous studies have established an association but few had been
able to establish an exposure-response relationship, perhaps due to small sample size or poor exposure assessment.
The results suggest that relatively low intensity exposure to pesticides may increase risks. On the other hand, they suggest that in general, risk from
solvents and metals are less important in this respect.
Overall, the exposure-response relationship suggests that pesticide exposure may be a causative and potentially modifiable risk factor. This has
implications for occupational and, perhaps, recreational users of these agents. Further research is needed to establish which pesticides are
associated with this effect.
In this regard, in July 2006 the European Commission adopted a new strategy aimed at improving the way pesticides are used across the EU. It
complements existing EU legislation controlling which pesticides can actually be placed on the market. The strategy foresees measures such as
national action plans, training for professional users and distributors, certification and control of application equipment, protection of the aquatic
environment, and restricting or banning the use of pesticides in specific areas.