Occupational pesticide exposure and symptoms of attention deficit hyperactivity disorder in adolescent pesticide applicators in Egypt

Diane Rohlman, Ahmed Ismail, Matthew R. Bonner, Gaafar Abdel Rasoul, Olfat Hendy, Lizette Ortega Dickey, Kai Wang, James R. Olson

Research output: Contribution to journalArticle

Abstract

Background: Exposure to environmental chemicals, including organophosphorus pesticides, is associated with behavioral disorders such as attention deficit hyperactivity disorder (ADHD). However, the impact of occupational pesticide exposure on ADHD development in adolescents has not been examined. Objective: We examined the association between exposure to chlorpyrifos and ADHD symptoms among adolescents in Egypt. Methods: Adolescent pesticide applicators and non-applicators, 12–21 years old, participated in a 10-month longitudinal study examining health effects from pesticide exposure. Repeated urine and blood samples were collected at various time points during the 10-months to assess biomarkers of chlorpyrifos exposure (urinary trichloro-2-pyridinol or TCPy) and effect (blood acetyl cholinesterase activity and butyryl cholinesterase activity). Parents from a subset of the cohort (N = 64) completed the Short Form of Conners’ Parent Rating Scale – Revised. Poisson regressions were used to examine the associations between the number of ADHD symptoms and occupation and biomarkers. Results: Pesticide applicators had significantly more symptoms of ADHD than participants in the non-applicator group. Urinary TCPy levels were associated with increased symptoms, demonstrating a dose-response effect. Applicators with ADHD reported applying pesticides for more hours during the application season and had greater cumulative TCPy levels than participants without ADHD. One fourth of all applicators met the criteria for an ADHD diagnosis (having 6 or more reported symptoms). Conclusions: This study provides preliminary evidence of an association between occupational exposure to chlorpyrifos and ADHD symptoms among adolescent pesticide applicators in spite of its limited small sample size. There is a critical need to investigate the susceptibility of children and adolescents to repeated occupational and environmental exposures to pesticides because the developing brain may be uniquely sensitive to the neurotoxic effects of these agents.

Original languageEnglish (US)
Pages (from-to)1-6
Number of pages6
JournalNeuroToxicology
Volume74
DOIs
StatePublished - Sep 1 2019

Fingerprint

Applicators
Egypt
Occupational Exposure
Attention Deficit Disorder with Hyperactivity
Pesticides
Chlorpyrifos
Cholinesterases
Biomarkers
Environmental Exposure
Blood
Association reactions
Adolescent Development
Occupations
Brain
Sample Size
Longitudinal Studies
Health
Parents
Urine

Keywords

  • ADHD
  • Adolescent
  • Organophosphate pesticides

ASJC Scopus subject areas

  • Neuroscience(all)
  • Toxicology

Cite this

Occupational pesticide exposure and symptoms of attention deficit hyperactivity disorder in adolescent pesticide applicators in Egypt. / Rohlman, Diane; Ismail, Ahmed; Bonner, Matthew R.; Abdel Rasoul, Gaafar; Hendy, Olfat; Ortega Dickey, Lizette; Wang, Kai; Olson, James R.

In: NeuroToxicology, Vol. 74, 01.09.2019, p. 1-6.

Research output: Contribution to journalArticle

Rohlman, D, Ismail, A, Bonner, MR, Abdel Rasoul, G, Hendy, O, Ortega Dickey, L, Wang, K & Olson, JR 2019, 'Occupational pesticide exposure and symptoms of attention deficit hyperactivity disorder in adolescent pesticide applicators in Egypt', NeuroToxicology, vol. 74, pp. 1-6. https://doi.org/10.1016/j.neuro.2019.05.002
Rohlman, Diane ; Ismail, Ahmed ; Bonner, Matthew R. ; Abdel Rasoul, Gaafar ; Hendy, Olfat ; Ortega Dickey, Lizette ; Wang, Kai ; Olson, James R. / Occupational pesticide exposure and symptoms of attention deficit hyperactivity disorder in adolescent pesticide applicators in Egypt. In: NeuroToxicology. 2019 ; Vol. 74. pp. 1-6.
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abstract = "Background: Exposure to environmental chemicals, including organophosphorus pesticides, is associated with behavioral disorders such as attention deficit hyperactivity disorder (ADHD). However, the impact of occupational pesticide exposure on ADHD development in adolescents has not been examined. Objective: We examined the association between exposure to chlorpyrifos and ADHD symptoms among adolescents in Egypt. Methods: Adolescent pesticide applicators and non-applicators, 12–21 years old, participated in a 10-month longitudinal study examining health effects from pesticide exposure. Repeated urine and blood samples were collected at various time points during the 10-months to assess biomarkers of chlorpyrifos exposure (urinary trichloro-2-pyridinol or TCPy) and effect (blood acetyl cholinesterase activity and butyryl cholinesterase activity). Parents from a subset of the cohort (N = 64) completed the Short Form of Conners’ Parent Rating Scale – Revised. Poisson regressions were used to examine the associations between the number of ADHD symptoms and occupation and biomarkers. Results: Pesticide applicators had significantly more symptoms of ADHD than participants in the non-applicator group. Urinary TCPy levels were associated with increased symptoms, demonstrating a dose-response effect. Applicators with ADHD reported applying pesticides for more hours during the application season and had greater cumulative TCPy levels than participants without ADHD. One fourth of all applicators met the criteria for an ADHD diagnosis (having 6 or more reported symptoms). Conclusions: This study provides preliminary evidence of an association between occupational exposure to chlorpyrifos and ADHD symptoms among adolescent pesticide applicators in spite of its limited small sample size. There is a critical need to investigate the susceptibility of children and adolescents to repeated occupational and environmental exposures to pesticides because the developing brain may be uniquely sensitive to the neurotoxic effects of these agents.",
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AU - Ismail, Ahmed

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AU - Hendy, Olfat

AU - Ortega Dickey, Lizette

AU - Wang, Kai

AU - Olson, James R.

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AB - Background: Exposure to environmental chemicals, including organophosphorus pesticides, is associated with behavioral disorders such as attention deficit hyperactivity disorder (ADHD). However, the impact of occupational pesticide exposure on ADHD development in adolescents has not been examined. Objective: We examined the association between exposure to chlorpyrifos and ADHD symptoms among adolescents in Egypt. Methods: Adolescent pesticide applicators and non-applicators, 12–21 years old, participated in a 10-month longitudinal study examining health effects from pesticide exposure. Repeated urine and blood samples were collected at various time points during the 10-months to assess biomarkers of chlorpyrifos exposure (urinary trichloro-2-pyridinol or TCPy) and effect (blood acetyl cholinesterase activity and butyryl cholinesterase activity). Parents from a subset of the cohort (N = 64) completed the Short Form of Conners’ Parent Rating Scale – Revised. Poisson regressions were used to examine the associations between the number of ADHD symptoms and occupation and biomarkers. Results: Pesticide applicators had significantly more symptoms of ADHD than participants in the non-applicator group. Urinary TCPy levels were associated with increased symptoms, demonstrating a dose-response effect. Applicators with ADHD reported applying pesticides for more hours during the application season and had greater cumulative TCPy levels than participants without ADHD. One fourth of all applicators met the criteria for an ADHD diagnosis (having 6 or more reported symptoms). Conclusions: This study provides preliminary evidence of an association between occupational exposure to chlorpyrifos and ADHD symptoms among adolescent pesticide applicators in spite of its limited small sample size. There is a critical need to investigate the susceptibility of children and adolescents to repeated occupational and environmental exposures to pesticides because the developing brain may be uniquely sensitive to the neurotoxic effects of these agents.

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KW - Adolescent

KW - Organophosphate pesticides

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