Traumatic brain injury, paraquat exposure, and their relationship to Parkinson disease.
Level 4 - case-series / case-control
Case-control study
PubMed 23150532 · doi:10.1212/WNL.0b013e3182749f28
What was done
A case-control study investigated the association of traumatic brain injury (TBI) and ambient paraquat exposure with Parkinson disease (PD) risk. The study enrolled 357 incident idiopathic PD cases and 754 population controls in central California between 2001 and 2011. TBI history was self-reported (defined as head injury with loss of consciousness >5 minutes). Ambient paraquat exposure within 500 m of residences and workplaces since 1974 was estimated using a validated geographic information system (GIS) based on state pesticide application records. Adjusted odds ratios (AOR) were computed using logistic regression.
What was found
TBI alone was associated with a 2-fold increase in PD risk (AOR 2.00, 95% CI 1.28-3.14), while ambient paraquat exposure alone showed a weaker association (AOR 1.36, 95% CI 1.02-1.81). Participants with both TBI and paraquat exposure had a 3-fold higher risk of developing PD compared to those exposed to neither risk factor (AOR 3.01, 95% CI 1.51-6.01).
Why it matters
This study provides human epidemiologic evidence that mechanical trauma and environmental neurotoxic pesticide exposure may act synergistically in a more than additive manner to elevate Parkinson disease risk.
Limits
TBI assessment relied on retrospective self-report, which is susceptible to recall bias. Paraquat exposure was estimated using geographical proximity to agricultural applications rather than direct personal exposure or biomarker measurements.
Cited by
- supports Paraquat exposure and traumatic brain injury with loss of consciousness interact synergistically to amplify the risk of developing Parkinson's disease.