A large meta-analysis worldwide shows these chemicals pose a higher likely risk for the disease
Dr.’s Emanuele Cereda, MD, PhD, San Matteo Hospital Pavia Fondazione IRCCS and Gianni Pezzoli, MD, Parkinson Institute, ICP, Milan, examined the risk of Parkinson’s disease associated with exposure to pesticides and solvents using meta-analyses of data from cohort and case-control studies.
Inclusion criteria for this meta-analysis included prospective cohort and case-control studies providing risk and accuracy estimates related to Parkinson’s disease (PD) exposure to pesticides or solvents or to agents of exposure were eligible. The collection in risk estimates associated with objective study quality was also investigated.
A total of 104 studies/3,087 citations fulfilled inclusion criteria for meta-analysis that looked at exposure to weed, fungus, rodent or bug killers, and solvents and the risk of developing Parkinson’s disease. Studies that evaluated the proximity of exposure, such as country living, work occupation and well water drinking were also included.
The research found that exposure to bug or weed killers and solvents increased the risk of developing Parkinson’s disease by 33 to 80 percent. In controlled studies, exposure to the weed killer paraquat or the fungicides maneb and mancozeb was associated with two times the risk of developing the disease.
In high-quality case-control studies including an appreciable number of cases (>200), heterogeneity remained significantly high (>40%) only for insecticides, organochlorines, organophosphates, and farming; also, the risk associated with rural living was found to be significant.
In their conclusion the team writes “The literature supports the hypothesis that exposure to pesticides or solvents is a risk factor for PD. Further prospective and high-quality case-control studies are required to substantiate a cause-effect relationship. The studies should also focus on specific chemical agents.
Dr. Cereda comments “We didn’t study 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, affected Parkinson’s risk.” He adds “However, our study suggests that the risk increases in a dose response manner as the length of exposure to these chemicals increases.”
The study was supported by the Grigioni Foundation for Parkinson’s Disease and the IRCCS University Hospital San Matteo Foundation.
The research appears in the May 28, 2013, print issue of Neurology®
According to the Parkinson’s Disease Foundation as many as one million Americans live with Parkinson’s disease, which is more than the combined number of people diagnosed with multiple sclerosis, muscular dystrophy and Lou Gehrig’s disease.
Parkinson’s disease is the most common of the major movement disorders, a category of conditions in which a malfunction in the nervous system affects communication between the brain and the muscles. Other common movement disorders include dystonia, characterized by involuntary muscle spasms, and essential tremor, a neurological condition in which part of the body shakes or trembles.
More information on Parkinson’s Disease induced by pesticides can be viewed online at BeyondPesticides.org.
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