(Beyond Pesticides, February 17, 2011) According to a recent investigative report, a company known for conducting scientific research for the pesticide industry has, in an attempt to refute research linking pesticides to Parkinson’s disease, paid a U.S. government agency, the National Institute for Occupational Safety and Health (NIOSH), to prove that certain pesticides are safe. According to the report, the company, Exponent Inc., is a member of CropLife America, a trade group that represents pesticide manufacturers, and also has worked regularly for Syngenta, which makes paraquat, one of the chemicals it is looking prove as safe. Specifically, the company is looking to refute the research which shows that even small amounts of agricultural chemicals, maneb and paraquat, when combined, can raise the risk of Parkinson’s disease. According to the report, managing scientist of Exponent, Laura McIntosh, PhD, said in an interview that the company donated the money and sought participation at NIOSH to enhance the credibility of its study of maneb and paraquat; they wanted to make their research “bulletproof.” NIOSH is a division of the Centers for Disease Control and Prevention (CDC). Generally, government agencies are supposed to be unbiased, and federal ethics rules prohibit employees from accepting money […]

(Beyond Pesticides, February 16, 2011) Many agricultural pesticides —including some previously untested and commonly found in food— disrupt male hormones, according to new tests conducted by British scientists. Meanwhile, U.S. researchers at the National Institutes of Health have found that people who used two specific varieties of pesticide were 2.5 times as likely to develop Parkinson’s disease. Pesticides Impact Male Hormones Evidence suggests that there is widespread decline in male reproductive health and anti-androgenic pollutants, also known as endocrine disruptors, may play a significant role. Thirty out of 37 pesticides tested by the researchers at the University of London altered male hormones, including 16 that had no known hormonal activity until now. There was some previous evidence for the other 14. Most are fungicides applied to fruit and vegetable crops, including strawberries and lettuce. The study, “Widely Used Pesticides with Previously Unknown Endocrine Activity Revealed as in Vitro Anti-Androgens,” is published in Environmental Health Perspectives. The British researchers screened the chemicals using in vitro assays, which use human cells to check whether the pesticides activate or inhibit hormone receptors in cells that turn genes on and off. Scientists, however, are uncertain what actually happens in the human body at the […]

(Beyond Pesticides, June 16, 2010) Men with certain genetic variations who were exposed to some toxic pesticides that are now largely banned run an increased risk of developing Parkinson’s disease, French scientists said Monday. In a study published in Archives of Neurology, entitled “Interaction Between ABCB1 and Professional Exposure to Organochlorine Insecticides in Parkinson Disease,” French researchers found that among men exposed to pesticides such as DDT, carriers of the gene variants are three and a half times more likely to develop Parkinson’s than those with the more common version of the gene. The scientists think the brains of people with the gene variant fail to flush out toxic chemicals as efficiently as those with common versions of the gene, suggesting that environmental as well as genetic factors are important in the risk of Parkinson’s. Alexis Elbaz, MD, PhD and Fabien Dutheil, PhD, of France’s National Institute for Health and Medical Research (INSERM) studied 101 men with Parkinson’s and 234 without the disease to look at links between organochlorine exposure and Parkinson’s disease. The study includes only men, and all of them had high levels of exposure to pesticides through their work as farmers. The scientists found the link was […]

(Beyond Pesticides, January 11, 2010) Yet another study has been published that further supports the causative link between pesticide exposure and Parkinson’s disease. The study, funded by the National Institute of Environmental Health Sciences (NIEHS), is published in the January issue of Epidemiology. The University of California, Los Angeles researchers looked at the association between Parkinson’s disease, organophosphate pesticides and the common gene variant, paraoxonase-1 gene Leu-Met 55 polymorphism (PON1-55 MM). The findings show that study participants with two copies of gene variant have a significantly increased risk of developing Parkinson’s disease when exposed to certain organophosphate pesticides used in agriculture. The population-based case-control study examined the DNA of 351 incident cases and 363 controls from three rural counties in California. The researchers then used pesticide usage reports and a geographic information system (GIS) approach to determine the study participants’ residential exposure to organophosphates. The PON1 gene codes for an enzyme that metabolizes organophosphate pesticides. Individuals with the variant MM PONI1-55 genotype that are exposed to organophosphates exhibit more than twice the risk of Parkinson’s disease compared to carriers of wildtype or heterozygous genotype and no exposure. In regards to exposure to diazinon, carriers of variant MM PONI-55 genotype show […]

(Beyond Pesticides, September 16, 2009) A new study published in the September issue of Archives of Neurology reports that the risk of Parkinsonism doubled with increased occupational exposure to pesticides, including eight agents associated with experimental Parkinsonism. These data add to the growing number of studies that lend credence to a causative role of certain pesticides in neurological disorders. The study, “Occupation and Risk of Parkinsonism: A Multicenter Case-Control Study,” set out to investigate occupations, specific job tasks, or exposures and risk of parkinsonism in collaboration with eight movement disorders centers in North America including, the Parkinson’s Institute, CA, Department of Neurology, Baylor College of Medicine and Department of Neurology, Beth Israel Medical Center, New York. The investigation focused on five occupations previously suggested as posing an increased risk of Parkinsonism: agriculture, education, healthcare, welding, and mining. This examination of toxicant exposures included solvents and pesticides putatively associated with Parkinsonism. 519 people with Parkinson’s disease and 511 similar people who did not have Parkinson’s were studied. Overall, the study finds that those whose jobs involve using pesticides are 80 percent more likely to develop the condition. The data reveals that any exposure to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) almost triples […]

(Beyond Pesticides, August 7, 2009) A recent study published in the journal Environmental Health Perspectives has added to evidence that certain pesticides significantly increase one’s risk of developing Parkinson’s disease (PD). Researchers found that rural residents who drank private well water within 500 meters of fields sprayed with certain pesticides had an increased – up to 90 percent – risk of developing PD, and those with Parkinson’s “were more likely to have consumed private well water, and had consumed it on average 4.3 years longer.” The study evaluated more than 700 people, including carefully chosen controls, in Fresno, Kent, and Tulare counties. 17 percent reported drinking private well water between 1974 and 1999. Researchers focused on wells’ proximity to agricultural fields sprayed with pesticides, since private wells are not regulated, and many are shallow enough to be contaminated by pesticides seeping into groundwater. Researchers looked at 26 pesticides and six in particular, “selected for their potential to pollute groundwater or because they are of interest for PD, and to which at least 10% of our population were exposed.” Those are: diazinon, chlorpyrifos, propargite, paraquat, dimethoate, and methomyl. Propargite exposure was most closely correlated with incidence of PD, with a 90 […]

(Beyond Pesticides, July 30, 2009) A new report from the Institute of Medicine (IOM) and sponsored by the U.S. Department of Veterans Affairs finds suggestive but limited evidence that exposure to Agent Orange and other herbicides used during the Vietnam War is associated with an increased chance of developing ischemic heart disease and Parkinson’s disease in Vietnam veterans. The report is the latest in a congressionally mandated series by IOM that every two years reviews the evidence about the health effects of these herbicides and a type of dioxin – TCDD – that contaminated some of the defoliants. A finding of “limited or suggestive evidence of an association” means that the evidence indicates there could be a link between exposure to a chemical and increased risk for a particular health effect, though conflicting results from studies, problems with how the studies were conducted, or other confounding factors limit the certainty of the evidence. Until now, the cumulative evidence had been inadequate to draw conclusions about whether these two conditions may be associated with veterans’ exposures to herbicides or TCDD. Ischemic heart disease – a condition characterized by reduced blood supply to the heart, which can lead to heart attack and […]

(Beyond Pesticides, June 8, 2009) A new epidemiological study finds that Parkinson’s disease patients who have been exposed to pesticides through their work show elevated rates of the disease. The researchers find that French farmworkers have nearly double the risk for the disease if exposed to pesticides, with a dose-effect for the number of years of exposure. When they looked at the three major classes of pesticides (insecticides, fungicides and herbicides), they find that the farmworkers who used insecticides had over a two-fold increase in the risk of Parkinson’s disease. A slightly higher risk is found for exposure to organochlorine insecticides. According to the study, these associations are stronger in men with older onset Parkinson’s disease than in those with younger onset Parkinson’s. The study, “Professional Exposure to Pesticides and Parkinson’s Disease,” published in Annals of Neurology, involved individuals affiliated with the French health insurance organization for agricultural workers who were frequently exposed to pesticides in the course of their work. Occupational health physicians constructed a detailed lifetime exposure history to pesticides by interviewing participants, visiting farms, and collecting a large amount of data on pesticide exposure. These included farm size, type of crops, animal breeding, which pesticides were used, […]

(Beyond Pesticides, March 16, 2009) Exposure to a mixture of the fungicide maneb and the herbicide paraquat significantly increases the risk of developing Parkinson’s disease, according to a new University of California, Berkeley study, “Parkinson’s Disease and Residential Exposure to Maneb and Paraquat from Agricultural Applications in the Central Valley of California.” Published in the American Journal of Epidemiology, the study findings show that exposure to both pesticides within 500 meters of an individual’s home increases the risk of developing Parkinson’s by 75 percent. For individuals 60 years of age or younger at the time of diagnosis, there is a more than four-fold increase in risk of the disease when exposed to a combination of maneb and paraquat and a more than doubling of risk when exposed to either maneb or paraquat alone. The Berkeley researchers used geographic information systems that analyzed data from California Pesticide Use Reports and land-use maps to calculate historical residential exposure to agricultural exposure to the two pesticides. From 1998 to 2007, the researchers enrolled 368 incident Parkinson’s disease cases and 341 population controls from California’s Central Valley and developed potential exposure estimates incurred between 1974 and 1999. Also published this month by some of […]

(Beyond Pesticides, March 2, 2009) Pesticide exposure and genetic variability in the dopamine transporter (DAT), a protein that plays a central role in dopaminergic neurotransmission of the brain, interact to significantly increase the risk factor for Parkinson’s disease, according to a new study by University of California, Los Angeles (UCLA) researchers. The population based case-control study, “Dopamine Transporter Genetic Variants and Pesticides in Parkinson’s Disease,” builds on the existing body of evidence of animal data and epidemiological studies that link exposure to pesticides, including gene-pesticide interactions, to Parkinson’s disease. The UCLA researchers, looking at incident Parkinson’s disease cases in three rural counties in Central California, find DAT increases the risk of Parkinson’s when individuals have occupational or residential exposure to pesticides. This is the first epidemiologic study of Parkinson’s disease that relies on pesticide data that is from a record-based source versus recall-based data relying on individuals’ memory. The second most common neurodegenerative disease affecting more than one million people in the U.S., 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. The new UCLA study is […]

(Beyond Pesticides, December 1, 2008) A new study by researchers at the University of California Los Angeles finds chronic exposure to commonly used dithiocarbamate fungicides, such as ziram, contribute to the development of Parkinson’s disease. According to the study, Ziram Causes Dopaminergic Cell Damage by Inhibiting E1 Ligase of the Proteasome, published in the Journal of Biological Chemistry, researchers screened several pesticides for their ability to interfere with the ubiquitin-proteasome system (UPS). Impaired UPS activity is reported in Parkinson’s disease patients’ brains. The researchers then focused on dithiocarbamate fungicides because they were found to be one of the most potent UPS inhibitors and are commonly used. The researchers discovered the mechanisms by which the UPS is impaired, showing that ziram and structurally related dithiocarbamates inhibit E1 ligase (a protein activating enzyme). Ziram is also found to increase alpha-synuclein (a protein expressed in the central nervous system) levels and selectively damages dopaminergic neurons in vitro. The study also cites unpublished data from a population-based study in central California that is determining pesticide exposure using state application registry, finding that individuals living within 500 meters of where ziram is applied are at three times the increased risk of developing Parkinson’s compared to […]

(Beyond Pesticides, September 19, 2008) Adding to the body of epidemiologic evidence linking pesticides to Parkinson’s Disease (PD), a recent study shows a correlation between 100 PD patients and the use of the pesticide rotenone. The study was conducted by physicians and researchers at The University of Texas Health Science Center at Tyler (UTHSCT) and an East Texas Medical Center physician.The study’s lead author is Aman Dhillon, MD, MS, assistant professor of occupational and environmental medicine at UTHSCT. Rotenone is highly toxic to fish and insects, but mildly toxic to warm-blooded animals and humans. It is made from the roots of tropical plants and is used in home gardens and in fisheries management to remove unwanted fish species, said Jeffrey Levin, MD, MSPH, chair of UTHSCT’s Department of Occupational Health Sciences. Dr. Levin is a co-author of the study, published recently in the peer-reviewed Journal of Agromedicine. A total of 184 people participated in the study: 100 had Parkinson’s disease and 84 did not, though they had other neurological disorders. All were patients of George M. Plotkin, MD, Ph.D., a neurologist with a special interest in Parkinson’s disease. Dr. Plotkin, medical director of the ETMC Movement Disorder Center, treats about […]

(Beyond Pesticides, March 31, 2008) Researchers studying related individuals who share environmental and genetic backgrounds find an association between pesticide use and Parkinson’s disease. The strongest links were between the disorder and use of herbicides and insecticides, such as organochlorines and organophosphates. The study, “Pesticide exposure and risk of Parkinson’s disease: a family-based case-control study,” was published March 28 online in the journal BMC Neurology. The research team from Duke University Medical Center and the University of Miami Miller School of Medicine Morris K. Udall Parkinson Disease Research Center of Excellence recruited 319 patients and over 200 relatives. They used telephone interviews to obtain histories of pesticide exposure, living or working on a farm, and well-water drinking. No association was found between Parkinson’s disease and well-water drinking or living or working on a farm, which are two commonly used proxies for pesticide exposures. Parkinson’s disease is a common neurological disorder affecting about 1 million people in the U.S. The disorder typically develops in later life resulting in symptoms such as tremors and muscle rigidity. Although variations in several genes have been identified that contribute to the disease, these rare genetic defects account for a small proportion of the overall prevalence […]