Medical professionals are still trying to understand all of the underlying causes of Parkinson’s disease, a progressive disease that sees the degeneration and death of motor neurons. A recent study has shed some light on a possible risk factor: the herbicide paraquat. According to the research published in the Journal of Occupational Medicine and Toxicology, working with this herbicide does not increase one’s risk of developing or dying from Parkinson’s.
Paraquat and Parkinson’s
Titled “Mortality from Parkinson’s disease and other causes among a workplace manufacturing paraquat: an updated retrospective cohort study,” this study examined the death certificates of over 950 people who were exposed to paraquat during the manufacturing from 1961 to 1995 across four different locations in the U.K. As environmental triggers are believed to play a role in the development of Parkinson’s, researchers wanted to examine paraquat as one of these potential triggers. This is partly due to the herbicide’s similarities to another chemical, MPTP, which has been linked to the neurodegenerative disease.
In the past, research has connected paraquat to a higher risk of Parkinson’s, but this retrospective study found otherwise, therefore prompting further research. In fact, the published report states that there were no health effects related to exposure to paraquat within the groups evaluated.
To discover this, the researchers utilized the mortality rates of England and Wales to compare the observed number of deaths to the actual number. From this, they were able to derive a standardized mortality ratio (SMR). They also calculated the mortality rate for Parkinson’s disease. When looking at these numbers, they found that the number of people dying from Parkinson’s within the study population was similar to that of the general population in England and Wales. In fact, males exposed to paraquat in the workplace experienced two deaths with causes related to Parkinson’s, while the general population recorded three deaths.
The researchers were unable to find a significant link between the length of time or level of exposure to paraquat, leading them to recommend further research. They also investigated workplace deaths related to other causes, such as lung cancer, heart and lung diseases, kidney disease, and other cancers. The only condition that was found at a higher rate among the workers than the general population was cancer, but there were no trends connected to the amount of duration of exposure to paraquat.
While the researchers acknowledged the limitations of their study – namely the fact that only death certificates were used for analysis – they stated that there were no connections between paraquat and Parkinson’s disease. They are calling for further research to better understand the possible link and other causes of the neurological disease.
About Parkinson’s Disease
Parkinson’s disease is a progressive disorder that affects the central nervous system (CNS). It is characterized by its effect on movement through five different stages. As the disease progresses, severity increases. Stage one is characterized by subtle tremors on one side of the body. In stage two symptoms are more noticeable, with tremors and rigidity on both sides of the body. Stage three brings loss of balance and slowed movement. Stage four makes it impossible for one to live independently. Stage five is the most severe, as patients cannot stand or walk. Hallucinations and delusions are common symptoms of this stage.
Parkinson’s disease occurs due to the death of motor neurons, some of which produce dopamine. Dopamine is important in the transmittance of messages to the muscles from the brain, so the loss of dopamine results in the loss of motor functions. Abnormal brain activity occurs when these neurons are lost. Doctors do not know why these motor neurons die, but they do suspect a few factors that play a role, such as genetics, environmental factors like toxins, and Lewy bodies.
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