Neurologic function among termiticide applicators exposed to chlorpyrifos

Area of Science:

• Environmental Health
• Neurotoxicology
• Occupational Health

Background:

• Chlorpyrifos is a widely used organophosphate pesticide with moderate toxicity.
• Widespread exposure in the U.S. population is indicated by detectable metabolite levels.
• Limited epidemiologic data exist on chlorpyrifos-specific neurotoxicity.

Purpose of the Study:

• To investigate the neurotoxic effects of chlorpyrifos exposure in termiticide applicators.
• To compare neurologic function between exposed workers and nonexposed controls.

Main Methods:

• Study included 191 current/former termiticide applicators and 189 controls.
• Evaluated neurologic function using clinical exams, nerve conduction, tremor, sensory, visual, and neurobehavioral tests.
• Measured urinary metabolite levels (3,5, 6-trichloro-2-pyridinol; TCP) to assess exposure.

Main Results:

• Exposed applicators had significantly higher urinary TCP levels than the general population.
• No significant differences were observed in most clinical examinations and quantitative neurobehavioral tests.
• Exposed group showed poorer performance in pegboard and postural sway tests, and reported more symptoms (memory, fatigue, emotional states).
• Eight men with prior chlorpyrifos poisoning showed patterns consistent with chronic organophosphate effects.

Conclusions:

• Clinical examination results for chlorpyrifos-exposed workers were largely reassuring.
• Self-reported symptoms and performance deficits in previously poisoned individuals raise concerns.
• Generalizability of findings may be limited due to specific study population characteristics.