Chlorpyrifos Pesticide Exposure Increases Parkinson's Disease Risk by 2.5-fold
A recent study from UCLA Health has revealed alarming findings regarding the long-term impact of exposure to the pesticide chlorpyrifos. The research found that individuals continuously exposed to this pesticide in their residential environment have a 2.5 times greater likelihood of developing Parkinson’s disease.
The study, published in the journal Molecular Neurodegeneration, combined large-scale human data with laboratory experiments. The results provided strong biological evidence of how this chemical damages dopamine-producing brain cells.
Researchers examined data from 829 Parkinson’s patients and 824 healthy individuals in California. By matching pesticide use records and residential and workplace locations over many years, the team successfully reconstructed patterns of chlorpyrifos exposure for each participant.
Beyond human data, experiments on mice and zebrafish reinforced these findings. Mice exposed to chlorpyrifos through inhalation for 11 weeks exhibited symptoms identical to Parkinson’s patients.
Experiments on zebrafish revealed deeper mechanisms. Chlorpyrifos disrupts autophagy—the natural cellular system for clearing damaged proteins. When this “cleaning” system is compromised, toxic proteins accumulate and trigger nerve cell death. Remarkably, when researchers restored this cleaning process in the laboratory, neurons became protected from damage.
“This study establishes chlorpyrifos as a specific environmental risk factor for Parkinson’s disease, not merely pesticides as a general class,” said Dr Jeff Bronstein, professor of Neurology at UCLA Health and senior author of the study.
“By demonstrating biological mechanisms in animal models, we have proven this relationship is likely causal. The finding that autophagy dysfunction drives neurotoxicity also directs us towards potential therapeutic strategies to protect vulnerable brain cells.”
Although household use of chlorpyrifos has been banned since 2001 and its use in the United States agricultural sector began to be restricted in 2021, this chemical remains in use on various types of crops in many parts of the world.
These findings open the door to new treatment methods focused on strengthening the natural protein-cleaning system within cells. Additionally, scientists recommend that individuals known to have been exposed to chlorpyrifos in the past receive stricter neurological monitoring for early detection of Parkinson’s disease.