Search

Background: Previous biomonitoring studies have shown that people in the rural population of Coquimbo, the major agricultural area in northern Chile are being occupationally and environmentally exposed to organophosphate/carbamate (OP/CB) pesticides. Given their harmful effects, this study had two aims; first, to evaluate the effect of cumulative or chronic exposure to OP/CB pesticides on the neurobehavioral performance of agricultural workers and rural inhabitants; second, to determine if changes in the neurobehavioral performance are associated to changes in blood biomarkers of OP/CB pesticides during the spray season, when exposure is higher., Methods: For the first aim, a cross sectional study of neurobehavioral performance in adult volunteers (men and women, 18-50 years-old, right-handed) was carried out in the pre-spray season. Sampling was done by convenience and a questionnaire was used to categorize participants depending on their level of chronic exposure, as either: occupationally exposed (OE, n = 87), environmentally exposed (EE, n = 81), or non-exposed controls or reference group (RG, n = 100). A neurobehavioral test battery consisting of 21 tests to measure cognitive, motor and emotional state was applied. For the second aim, neurobehavioral measures were taken a second time from EE and OE groups during the spray season, and their exposure corroborated by blood-based biomarker inhibition., Results: Lower neurobehavioral performance was observed in the pre-spray evaluation of EE and OE groups compared to the non-exposed, OE being the worst performing group. Seasonal exposure impaired performance in both exposure groups on all tests except those on attention and mood. Data modeling of the basal (pre-spray) measurements showed that the level of exposure was the best predictor of performance. During spraying, inhibition of BChE activity in the EE group was the best predictor of low performance in tests measuring logical, auditory and visual memory, inhibitory control of cognitive interference, constructional and planning abilities, executive functions, and motor speed and coordination., Conclusion: Long-term occupational or environmental exposure to pesticides caused impairment in neurobehavioral functioning, which worsened during the spraying season, mainly in EE. BChE inhibition was the best predictor for seasonal neurobehavioral changes in EE.

Chronic exposure to organophosphate pesticides is a worldwide public health concern associated with several psychiatric disorders and dementia. Most existing studies on the effects of pesticides only evaluate agricultural workers. Therefore, this study sought to establish if individuals indirectly exposed to pesticides, such as residents in agricultural areas, also suffer cognitive impairments. Neuropsychological evaluations were carried out on three groups (n=102): agricultural workers directly exposed to pesticides (n=32), individuals living in agricultural areas indirectly (i.e. environmentally) exposed to pesticides (n=32), and an unexposed control group (n=38). The assessed cognitive processes included memory, executive functions, attention, language praxis, and visuoconstruction. The direct exposure group performed significantly lower in executive function, verbal fluency, and visual and auditory memory tests than the indirect exposure group, which, in turn, performed worse than the unexposed group. Even after adjusting for age, gender, and educational level, both exposure groups showed higher rates of cognitive deficit than control individuals. In conclusion, both direct and indirect chronic exposure to pesticides affects cognitive functioning in adults and, consequently, actions should be taken to protect the health of not only agricultural workers, but also of residents in agricultural areas., (Copyright © 2017 Elsevier Inc. All rights reserved.)