Parkinson’s disease is a degenerative condition of the central nervous system that causes tremors in the body, difficulty walking, and trouble coordinating movements. In later stages, the disease also causes emotional and cognitive problems such as depression, hallucination, memory loss, and dementia. The onset of the illness is often later in life, usually after the age of 50. Awareness around Parkinson’s has increased in the last several years as more well-known cultural icons, such as actor Michael J. Fox and boxer Muhammad Ali, have come forward as Parkinson’s sufferers. Awareness about the connection between pesticides and Parkinson’s disease has also increased, especially in the last few months.
Up until very recently, connections between pesticides and Parkinson’s disease have been speculative and inconclusive. Instead, the disease, of which accounts have been found in the Bible and ancient Egyptian scrolls, had been considered to be idiopathic (stemming from no specific cause) or genetic (at least 5 percent of cases have been attributed to a gene mutation, and 15 percent of those with the disease also have a relative with Parkinson’s).
Neurologists at the University of California, Los Angeles (UCLA) have found connections between Parkinson’s disease and the herbicide paraquat, the fungicide maneb in 2009, and the pesticide ziram in 2011. Even more recently, in 2012, UCLA scientists have also found a connection between benomyl and the disease. While the fungicide benomyl has not been produced by its manufacturer DuPont since 2001, it still lingers in the environment. The pesticide was widely used in the United States for over 30 years, but was eventually banned because scientific evidence connected it to a variety of health problems, including cancers, malformations, and reproductive problems. Benomyl, according to the study, sets in motion a complex set of events inside the cells that eventually lead to Parkinson’s over time.
The paraquat, maneb, and ziram studies looked at Parkinson’s disease prevalence among residents of the California Central Valley, many of whom are farmworkers. Neither the most recent UCLA study looking at the pesticide benomyl, nor a previous study analyzing the connection between pesticides and Parkinson’s disease conducted at the German University Clinic Carl Gustav Carus, used human subjects, but instead used experimental models with lab animals such as mice and zebra fish. Many other previous studies of human subjects active in agriculture and farming, showed an above average incidence of Parkinson’s. One such study conducted by the National Institutes of Health (NIH) for example, showed users of the pesticides paraquat and rotenone are 2.5 times more likely to suffer from Parkinson’s compared to non-users.
That isn’t all. A 2006 Mayo Clinic study in Minnesota indicated that men who used pesticides were 2.4 times more likely to have Parkinson’s compared to men who did not use pesticides. A long term Harvard School of Public Health study showed similar results. In the study, which looked at over 140,000 men and women, those who reported any pesticide exposure were 70 percent more likely to have Parkinson’s disease than those who reported no exposure to pesticides. This study included men and women who were exposed to pesticides occupationally, as well as in their homes and gardens.
With over one billion pounds of pesticides used in U.S. agricultural fields, gardens, and parks, this connection cannot be ignored. While it is difficult to establish indubitable scientific proof that pesticides can indeed cause Parkinson’s, dozens of highly regarded scientific studies are building a strong argument for it.
Parkinson’s is both chronic and progressive, meaning that it persists over a long period of time, and that it gets worse as time goes on. Farmworkers who often cannot avoid working in and living near agricultural fields treated with pesticides are at great risk. This disease deteriorates their bodies, which they rely on to support their families—bending over, crouching, and stretching to pick the fruits and vegetables we all enjoy.
These studies show that both farmworkers and non-agricultural workers living near agricultural fields who are exposed to pesticide drift are affected. Pesticides used in the home and backyards have also been linked to Parkinson’s. We are all at risk the more pesticides are used around us. To find out how to better protect yourself and your family from pesticides, visit AFOP’s Health & Safety Programs webpage.