Common Pesticide Chlorpyrifos Linked to Over 2.5 Times Higher Parkinson’s Risk
A new study by researchers at the University of California, Los Angeles (UCLA) has found that prolonged exposure to the widely used pesticide chlorpyrifos is associated with more than a 2.5-fold increase in the risk of developing Parkinson’s disease. Chlorpyrifos, sprayed extensively on agricultural fields for decades, has been detected in the air and residential environments affecting millions worldwide. Although its residential use was banned in the U.S. in 2001 and agricultural restrictions followed, it remains in use in many countries.
The UCLA study combined epidemiological data from 829 Parkinson’s patients and 824 controls with detailed pesticide application records in California, correlating exposure levels based on participants’ residential and work locations. The findings showed a strong link between chlorpyrifos exposure and Parkinson’s risk independent of other factors. Laboratory experiments further demonstrated that mice exposed to chlorpyrifos aerosols developed motor impairments and lost dopamine-producing neurons, hallmark features of Parkinson’s disease. The pesticide also triggered brain inflammation and abnormal accumulation of alpha-synuclein protein, which disrupts neuronal function.
Additional tests on zebrafish revealed that chlorpyrifos impairs autophagy, the cellular process responsible for clearing damaged proteins and waste. This disruption leads to toxic protein buildup and increased vulnerability of nerve cells. Restoring autophagy or reducing alpha-synuclein levels protected neurons from damage, suggesting potential therapeutic targets.
Dr. Jeff Bronstein, lead UCLA neurologist on the study, emphasized that this research identifies chlorpyrifos as a specific environmental risk factor for Parkinson’s and elucidates a biological mechanism linking exposure to neurodegeneration. Dr. Vered Libne, a movement disorders specialist at Tel Aviv’s Ichilov Medical Center, highlighted the significance of uncovering a treatable pathway that could slow or prevent disease progression.
In Israel, chlorpyrifos use has been phased out since 2007, with complete bans on residential and agricultural applications by 2022. Despite this, biomonitoring shows that over 90% of children and adults still have detectable exposure levels, with a small percentage exceeding safety thresholds. The Israeli Ministry of Agriculture confirmed ongoing efforts to monitor and restrict pesticide use, aligning with international environmental agreements.
The researchers plan to investigate whether other pesticides similarly disrupt autophagy and explore treatments that enhance cellular cleanup processes to reduce Parkinson’s risk.
