Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High risk of Parkinson's disease for people exposed to pesticides near workplace

27.05.2011
Study first to implicate pesticide ziram as possible cause for disease

In April 2009, researchers at UCLA announced they had discovered a link between Parkinson's disease and two chemicals commonly sprayed on crops to fight pests.

That epidemiological study didn't examine farmers who constantly work with pesticides but people who simply lived near where farm fields were sprayed with the fungicide maneb and the herbicide paraquat. It found that the risk for Parkinson's disease for these people increased by 75 percent.

Now a follow-up study adds two new twists. Once again the researchers returned to California's fertile Central Valley, and for the first time have implicated a third pesticide, ziram, in the pathology of Parkinson's disease. Second, instead of looking just at whether people lived near fields that were sprayed, they looked at where people worked, including teachers, firefighters and clerks who worked near, but not in, the fields.

They found that the combined exposure to ziram, maneb and paraquat near any workplace increased the risk of Parkinson's disease (PD) threefold, while combined exposure to ziram and paraquat alone was associated with an 80 percent increase in risk. The results appear in the current online edition of the European Journal of Epidemiology.

"Our estimates of risk for ambient exposure in the workplaces were actually greater than for exposure at residences," said Dr. Beate Ritz, senior author and a professor of epidemiology at the UCLA School of Public Health. "And, of course, people who both live and work near these fields experience the greatest PD risk. These workplace results give us independent confirmation of our earlier work that focused only on residences, and of the damage these chemicals are doing."

In addition, Ritz noted, this is the first study that provides strong evidence in humans that the combination of the three chemicals confers a greater risk of Parkinson's than exposure to the individual chemicals alone. Because these pesticides affect different mechanisms leading to cell death, they may act together to increase the risk of developing the disorder: Those exposed to all three experienced the greatest increase in risk.

"Our results suggest that pesticides affecting different cellular mechanisms that contribute to dopaminergic neuron death may act together to increase the risk of PD considerably," said Ritz, who holds a joint appointment in the UCLA Department of Neurology.

Scientists knew that in animal models and cell cultures, such pesticides trigger a neurodegenerative process that leads to Parkinson's, a degenerative disorder of the central nervous system that often impairs motor skills, speech and other functions and for which there is no cure. The disease has been reported to occur at high rates among farmers and in rural populations, contributing to the hypothesis that agricultural pesticides may be partially responsible.

In the past, data on human exposure had been unavailable, largely because it had been too hard to measure an individual's environmental exposure to any specific pesticide.

"This stuff drifts," Ritz said. "It's borne by the wind and can wind up on plants and animals, float into open doorways or kitchen windows — up to several hundred meters from the fields."

So several years ago, Ritz and her colleagues developed a geographic information system–based tool that estimates human exposure to pesticides applied to agricultural crops, according to the distance from fields on which pesticides are sprayed. This GIS tool combined land-use maps and pesticide-use reporting data from the state of California. Each pesticide-use record includes the name of the pesticide's active ingredient, the amount applied, the crop, the acreage of the field, the application method and the date of application.

From 1998 to 2007, the researchers enrolled 362 people with Parkinson's and 341 controls living in the Central Valley, then obtained historical occupational and residential addresses from all the study participants. Employing their geographic information system model, they estimated ambient exposures to the pesticides ziram, maneb and paraquat, both at work and home, from 1974 to 1999.

The results reaffirmed what their previous research had suggested, that the data, "suggests that the critical window of exposure to toxicants may have occurred years before the onset of motor symptoms, when a diagnosis of Parkinson's is made."

Knowing that the fungicide ziram is commonly used in agriculture and suspecting its relationship to Parkinson's, Ritz turned to her colleague Jeff Bronstein, a UCLA professor of neurology and co-author of the study, for confirmation. His lab performed a genetic screen using genetically modified cells to identify pesticides that inhibit the breakdown of important proteins such as alpha-synuclein. Ziram was one of the best inhibitors they identified; they found, in fact, that synuclein accumulated in dopamine neurons, selectively killing them. When it was given systemically to rodents, it reproduced many of the features of Parkinson's disease.

"So the present study clearly demonstrates that exposure to ziram in humans is associated with a significant increased risk of developing PD," Bronstein said.

Funding for the study was provided by the National Institute of Environmental Health Sciences, he National Institute of Neurological Disorders and Stroke, the U.S. Department of Defense Prostate Cancer Research Program, and the American Parkinson's Disease Association.

Other authors included lead author Anthony Wang (UCLA), Sadie Costello (UC Berkeley) and Myles Cockburn and Xinbo Zhang (University of Southern California). The authors declare no conflict of interest.

The UCLA School of Public Health is dedicated to enhancing the public's health by conducting innovative research; training future leaders and health professionals; translating research into policy and practice; and serving local, national and international communities.

For more news, visit the UCLA Newsroom and UCLA News|Week and follow us on Twitter.

Mark Wheeler | EurekAlert!
Further information:
http://www.ucla.edu

More articles from Health and Medicine:

nachricht Electrical 'switch' in brain's capillary network monitors activity and controls blood flow
27.03.2017 | Larner College of Medicine at the University of Vermont

nachricht Laser activated gold pyramids could deliver drugs, DNA into cells without harm
24.03.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>