Longitudinal assessment of chlorpyrifos exposure and self-reported neurological symptoms in adolescent pesticide applicators

Abstract

ObjectivesOccupational exposure of organophosphorus pesticides, such as chlorpyrifos (CPF), in adolescents is of particular concern because of the potential vulnerability of the developing neurological system. The objectives of this study were to examine how neurological symptoms reported over the application season vary across time, whether these effects are reversible postapplication and if there are associations between CPF biomarkers and neurological symptoms in an adolescent study population.SettingThe longitudinal study was conducted in two agricultural districts of Menoufia Governorate, Egypt between April 2010 and January 2011.ParticipantsMale adolescent participants, including CPF applicators (n=57) and non-applicators (n=38), were recruited.Primary and secondary outcome measuresSelf-reported data for 25 neurological symptoms were collected at 32 time points over the 8-month period before, during and after the application season. Additionally, urine and blood samples were collected to measure urine trichloro-2-pyridinol (TCPy), a CPF-specific biomarker and blood cholinesterase activity.ResultsApplicators and non-applicators report the highest numbers of symptoms during the application season, followed by a reduction in symptoms after the application ended. Applicators reported a greater percentage of neurological symptoms, relative to baseline, than non-applicators after accounting for potential covariates. Among the applicators, cumulative TCPy was positively and significantly associated with the average percentage of symptoms (B=4.56, 95% CI 3.29 to 5.84; p<0.001). Significant associations (p=0.03–0.07) between the change in butyrylcholinesterase activity from the preapplication to the postapplication season and several domains of neurological symptoms were also found, even after adjusting for potential covariates.ConclusionsThese observations demonstrate changes in the reporting of symptoms across the application season, showing an increase in symptom reporting during application and recovery following the end of pesticide application. These findings reinforce the growing concern regarding the neurotoxic health effects of CPF in adolescent applicators in developing countries and the need for developing and implementing intervention programmes.

Neurological and mental health outcomes among conventional and organic farmers in Indiana, USA

“…Although a higher number of symptoms were included in previous surveys, in the presented study, some symptoms which were found to be non-specific or autonomic (e.g. dizziness, headache, nausea, loss of appetite) were excluded, and therefore could not fall under any specific subscale [13,15,16,31]. Data from this study also provided identical findings to those presented by a large US Agricultural Health Study (AHS) on pesticideexposed male farmers [15].…”

“…The survey questionnaire in the current study for the neurological symptoms was based on Swedish Q16 which, in different cultural settings, demonstrated the effects of pesticides on the nervous system among South African women farmers [28], Egyptian agricultural workers [13] exposed to organophosphorus pesticides, in addition to German [29] and Algerian [30] workers exposed to solvents. A modified version of Q16 was validated and used in a large US study on licensed pesticide applicators [15].…”

“…Associations of pesticide exposures with nervous system outcomes, such as abnormalities in nerve conduction, frequent neurological symptoms were demonstrated in epidemiological studies across the globe [10][11][12][13][14][15][16]. Pesticide exposures demonstrated dose-dependent associations with various mental health outcomes such as depressions and anxieties in several animal models [17][18][19].…”

Differences Between Rainy and Dry Seasons in Levels of Cholinesterase Activities and Psychological Distress due to Organophosphate Exposure among Farmworkers

“…In addition, a proportion of the farmworkers categorized suffering from moderate and severe mental disorders in rainy season dramatically increased in dry season (Table 3). The finding of this study was different from the result of a study conducted by Wesseling et al (2010) that found past poisoning with OP was associated with an overall excess of symptoms of psychological distress and a study conducted by [15] …”

Longitudinal assessment of occupational exposures to the organophosphorous insecticides chlorpyrifos and profenofos in Egyptian cotton field workers

“…The toluene extract was then derivatized with BSTFA at 70°C for 1 hour and analyzed by gas chromatography-micro electron capture detection (GC/μECD). Urine specimens were analyzed for TCPy (the detoxified metabolite of CPF) by negative-ion chemical ionization gas chromatography–mass spectrometry, using 13C-15N-3,5,6-TCPy as an internal standard, as described previously (Crane et al, 2013; Farahat et al, 2011; Farahat et al, 2010; Khan et al, 2014). Briefly, samples for TCPy analyses were hydrolyzed with hydrochloric acid, extracted with toluene and derivatized using MTBSTFA.…”