Paraquat Pesticide and Parkinson’s Disease: A Neglected Connection

The agricultural industry has long relied on the use of pesticides to maintain productivity and protect crops from pests and diseases. One such pesticide, Paraquat, has been a staple in farming communities for decades. However, recent studies and legal actions have brought to light potential health risks associated with the use of this herbicide, particularly in relation to Parkinson’s Disease. In this article, we will explore the connection between Paraquat and Parkinson’s, the controversy surrounding the studies conducted on the subject, and the calls for more robust and independent research.

Paraquat, a herbicide manufactured by Syngenta, has been used extensively in agriculture since its introduction in the 1960s. It is particularly effective in killing weeds in crops such as corn, soybeans, and cotton. However, concerns about its health risks have been growing in recent years. One of the most significant health issues linked to Paraquat is Parkinson’s Disease.

Former farmer Larry Wyles, from Lebanon, Pennsylvania, is one of the plaintiffs in the ongoing legal action against Syngenta in the US. Mr. Wyles, who was diagnosed with Parkinson’s Disease in 2002, used Paraquat on his own farm for over two decades and also as a child on his father’s farm. He recalls the difficulties of cleaning the sprayer nozzles and the exposure to the herbicide that came with the job. Mr. Wyles believes that Syngenta “ought to be banned from making Paraquat ever again. They should be told to take it off the shelves today.”

Syngenta insists that there is no evidence linking Paraquat to Parkinson’s Disease. However, legal documents obtained by the BBC reveal that the company only looked at death certificates, rather than medical records, of workers at its Widnes site. This approach was criticized by experts, who argue that Parkinson’s Disease was underreported on death certificates at the time.

Charity Parkinson’s UK is now calling for “more robust and independent research” into any link between pesticides, including Paraquat, and Parkinson’s. The organization’s CEO, Steve Ford, stated that “it is essential that we understand the potential risks associated with pesticides and take appropriate action to protect public health.”

The controversy surrounding the studies conducted on Paraquat and Parkinson’s Disease is not limited to the US. In the UK, Professor Peter Hobson, a clinical healthcare scientist, carried out a study in 2018 to determine whether death certificates accurately recorded Parkinson’s Disease. He found that employing death certificates alone to determine increased risk of developing any neurological condition is “very weak and will always have questionable reliability.”

Professor Bas Bloem, director of the Radboudumc Center of Expertise for Parkinson & Movement Disorders in the Netherlands, believes that “scientists across the globe are convinced Paraquat is a cause of Parkinson’s.” He points to the most recent epidemiological study, carried out by UCLA’s Department of Neurology and published this month, which found that Paraquat exposure increases the risk of Parkinson’s Disease.

Syngenta’s own workers’ mortality study, which rejected any link between Paraquat and Parkinson’s Disease in 2011 and again in 2021, has been criticized for its methodology. Professor Bloem insists that “without a careful clinical analysis, just using mortality as a crude outcome has very limited value.”

Independent medical experts in the UK have also expressed concerns about the weak methodology used in Syngenta’s study. One of these experts is Professor David Dexter, director of research at Parkinson’s UK. He states that while the evidence is not yet strong enough to prove that pesticides, including Paraquat, directly cause Parkinson’s, international studies “overall suggest that exposure to pesticides may increase risk of the condition.”

The US Environmental Protection Agency (EPA) is currently reviewing the herbicide’s use and is looking at what measures might be needed to mitigate any health risks. In its draft report, the EPA states that for an outcome like Parkinson’s Disease, mortality is unlikely to be a reliable indicator for evaluating an association.

In conclusion, the connection between Paraquat and Parkinson’s Disease is a complex and controversial issue. While Syngenta maintains that there is no evidence linking the herbicide to the disease, numerous studies and legal actions suggest otherwise. The controversy surrounding the studies conducted on the subject highlights the need for more robust and independent research into the potential health risks associated with Paraquat and other pesticides. As the agricultural industry continues to rely on these chemicals, it is essential that we understand their potential risks and take appropriate action to protect public health.