(Beyond Pesticides, May 30, 2013) New research published in the journal Neurology further supports the causative link between pesticide exposure and Parkinson’s disease. Emanuel Cereda, M.D., Ph.D., of the IRCCS university Hospital San Matteo Foundation in Pavia, Italy, and coauthor Gianni Pezzoli, M.D., analyzed 104 studies published between 1975 and 2011 to determine the link between pesticides and solvents to Parkinson’s disease.
The researchers analyzed exposure using information on proximity to large farms likely to use pesticides, likelihood of well water consumption, and occupations that cause greater exposure to pesticides and solvents used to kill weeds, insects, fungus, and rodents. Overall, researchers found exposure to pesticides increased the risk of developing the disease by 33% to 80%. Some pesticides were considered to be of higher risk than others, with weed killers like paraquat and fungicides maneb and mancozeb causing twice the risk for development of Parkinson’s disease. While risk increased the longer people were exposed to pesticides, researchers indicate there is still a need for further research on the chemical threshold for harm to the brain.
The study builds on recent research that has linked Parkinson’s disease to pesticide exposure. In a 2011 article published in the journal Molecular Neurodegeneration, researchers at the University of Missouri School of Medicine invented a new antibody that allowed them to detect how oxidative stress affected proteins when exposed to a variety of environmental toxins, such as the pesticide rotenone. In another study, individuals with certain genetic factors that are exposed to organophosphates exhibited more than twice the risk of Parkinson’s disease compared to others without exposure. Another recent publication found that rural residents who drank contaminated well water had an increased (up to 90 percent) risk of developing Parkinson’s.
The research adds to the body of knowledge on the role of pesticide exposure in diseases like Parkinson’s.”I think the study is actually a big advance in our research knowledge of the relation between chemical exposures and the basic neurological injuries,” said Arch Carson, Ph.D., at the University of Texas School of Public Health in Houston. “This report is the first to show that there is a positive relationship between not only insecticides and herbicides but also some other solvent chemicals to which many people are exposed and the development of Parkinson’s syndrome.”
The second most common neurodegenerative disease, Parkinson’s disease occurs when nerve cells in the substantia nigra region of the brain are damaged or destroyed and can no longer produce dopamine, a nerve-signaling molecule that helps control muscle movement. People with Parkinson’s have a variety of symptoms including loss of muscle control, trembling and lack of coordination. They may also experience anxiety, constipation, dementia, depression, urinary difficulties, and sleep disturbances. Over time, symptoms intensify. At least one million Americans have Parkinson’s and about 50,000 new cases are diagnosed each year. With less than one percent of cases caused by genetics, researchers have been looking for the potential risk factors for developing Parkinson’s disease.
For more information on the latest research linking pesticides and Parkinson’s disease, see Beyond Pesticides’ Pesticide Induced Diseases Database (PIDD), or read the Parkinson’s Disease article from the Spring 2008 issue of Pesticides and You.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.