Previous studies have linked head trauma and toxin exposure to Parkinson’s disease, a chronic movement disorder that often causes a person to experience tremors and loss of coordination. But according to Reuters, a recent study conducted at the University of Los Angeles found that adults who suffered a head injury and who were exposed to the herbicide paraquat had a three-fold increased risk of developing Parkinson’s disease.
Researchers chose a sample of people who live in the agricultural region of central California and surveyed more than 1,000 adults who were 35 and older. Out of the sample, 357 people had Parkinson’s disease, and 754 people did not. Both groups were asked to report past traumatic head injuries, classified as staying unconscious for five minutes or more, and the research team used work and home addresses to determine their proximity to paraquat, a pesticide that has been sprayed in the area since 1974.
Findings were reported by the American Academy of Neurology, which revealed that adults who suffered a past TBI and were exposed to the pesticide had a nearly three-fold increased risk of developing Parkinson’s disease. Both factors have been previously tied on their own to an increased risk of the disease, but the dramatic tripling of the risk shows that there is a link between the combination of the two factors and Parkinson’s.
Head injuries may make the brain more susceptible to the effects of pesticides because ofchanges to the neurons. TBIs increase inflammation in the brain and disrupt the barrier that separates circulating blood and brain fluid. However, many experts say that other factors, such as gender, race, smoking, and family history still play a role in the development of Parkinson’s disease, which has no definitive causes.
Although the findings demonstrate a link between head injury, toxin exposure, and Parkinson’s disease, further study is needed since it’s possible to find many linkages in any data set.
Dr. David Simon, associate professor of neurology at Beth Israel Deaconess Medical Center in Boston, notes how the survey emphasizes the importance of considering multiple Parkinson’s risk factors and the growing harmful effects of pesticide exposure: “Based on the current study, this recommendation to avoid heavy pesticide exposure may be particularly important for people who have a history of significant head trauma with loss of consciousness for more than 5 minutes, as they may be particularly susceptible to the subsequent effects of pesticide exposure.”