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Neurobehavioral performance among agricultural workers and pesticide applicators: a meta-analytic study
  1. A A Ismail1,2,
  2. T E Bodner3,
  3. D S Rohlman4
  1. 1Department of Family and Community Medicine, Faculty of Medicine, Jazan University, Gizan, Saudi Arabia
  2. 2Public Health and Community Medicine Department, Faculty of Medicine, Menoufia University, Shebin Elkom, Egypt
  3. 3Department of Psychology, Cramer Hall, Portland State University, Portland, Oregon, USA
  4. 4Center for Research on Occupational and Environmental Toxicology, Oregon Health and Sciences University, Portland, Oregon, USA
  1. Correspondence to Dr Ahmed Ismail, Family and Community Medicine Department, Faculty of Medicine, Jazan University, Gizan 114, Saudi Arabia; aa-ismail{at}


Chronic low level exposure of agricultural workers and applicators to pesticides has been found to be associated with different degrees of decrement in cognitive and psychomotor functions. The goal of this study was to use meta-analysis to (1) identify and quantify neurobehavioral deficits among agricultural workers and pesticide applicators, and (2) analyse the potential confounders or moderators of these neurobehavioral deficits. Seventeen studies, reporting on 21 independent cohort groups, were included in the meta-analysis. These studies involved 16 neuropsychological tests providing 23 different performance measures that constitute the neurobehavioral constructs. All tests and measures of the neurobehavioral functions of attention, visuomotor integration, verbal abstraction and perception constructs showed significant decrements for exposed participants. One out of three tests of memory, two of five tests of sustained attention, and four of eight tests of motor speed constructs also showed significant decrements. Nine out of these 15 effect size distributions demonstrated significant heterogeneity across cohorts. A search for cohort-level variables (eg, agricultural workers vs applicators, duration of exposure, age and percentage of male participants) to explain this heterogeneity was largely unsuccessful. However, for one test, Block Design, the duration of exposure was positively associated with performance decrements. Furthermore, it was also found that performance decrements on this test were smaller for older participants. Increasing the number of studies and using more consistent methodologies in field studies are needed.

  • Neurobehavioral
  • pesticides
  • meta-analysis
  • neurobehavioural effects
  • epidemiology
  • occupational health practice
  • public health
  • exposure monitoring

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  • Funding This work was supported by the National Institute of Environmental Health Sciences (NIEHS, R21 ES017223, Rohlman). The content is solely the authors' responsibility and does not necessarily represent the official views of the NIEHS.

  • Competing interests The Oregon Health and Sciences University (OHSU) and DS Rohlman have a significant financial interest in Northwest Education Training and Assessment, LLC, a company that may have a commercial interest in the results of this research and technology. This potential individual and institutional conflict of interest has been reviewed and managed by OHSU (3-2010).

  • Provenance and peer review Not commissioned; externally peer reviewed.