Document Type


Peer Reviewed


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NLM Title Abbreviation

BMJ Open Respir Res

Journal/Book/Conference Title

BMJ Open

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DOI of Published Version


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Objectives Occupational 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. Setting The longitudinal study was conducted in two agricultural districts of Menoufia Governorate, Egypt between April 2010 and January 2011. Participants Male adolescent participants, including CPF applicators (n=57) and non-applicators (n=38), were recruited. Primary and secondary outcome measures Self-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. Results Applicators 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



Journal Article Version

Version of Record

Published Article/Book Citation

BMJ Open 4:3 (2014) pp. 1-11. doi:10.1136/bmjopen-2013-004177


Copyright 2014 Khalid Khan, Ahmed A. Ismail, Gaafar Abdel Rasoul, Matthew R. Bonner, Michael R. Lasarev, Olfat Hendy, Manal Al-Batanony, Alice L. Crane, Steven T. Singleton, James R. Olson, Diane S. Rohlman

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Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.