uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Pyrethroids exposure and neurobehavioral performance in school age children in rural Nicaragua
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences. (Occupational and Environmental Medicine)
Central American Institute for Studies on Toxic Substances (IRET), Universidad Nacional, Heredia, Costa Rica.
National Institute of Public Health (INSP), Cuernavaca, Morelos, Mexico.
Centre for Research in Health, Work and Environment (CISTA), National Autonomous University of Nicaragua (UNAN-León), León, Nicaragua.
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Objective: This cross-sectional study explored whether pre or postnatal pyrethroid exposure impaired cognitive performance and behavior in school-aged children from a rural area in Nicaragua.

Methods: Pyrethroid exposure was assessed in 110 children age 7-9, attending grade 1-3, with cumulative parental pyrethroid use indices of hours of spraying, during pregnancy, the first year of life, and older than age one. Cypermethrin accounted for most of the pyrethroid use. Cognitive performance of the children was evaluated with 12 sub-tests and total IQ of Wechsler Intelligence Scale for Children (WISC IV), grouped into indices for perceptual reasoning, verbal comprehension, working memory, and processing speed. Behavior at school was measured with the oppositional, cognitive problem/inattention, hyperactivity and ADHD index subscales of the Conners’ Teacher Rating Scale-Revised:Short form (CTRS-R:S). One year later, the pyrethroid metabolite 3-PBA was measured in 211 urine samples from 74 children (median 3.3 µg/g creatinine, max. 547) and the effect of recent exposure on cognitive and behavior was assessed with a shortened battery. 


Pyrethroid exposure indices during the first year of life significantly decreased performance of perceptual reasoning in children aged 7-9. For each 10-fold increasein hours of pyrethroid application , children’s performance on the Perceptual Reasoning Index decreased on average with 1.1 point.  Postnatal exposures, during the first year and after age 1, associated with hyperactivity and attention problem. Urinary 3-PBA levels were negatively associated with a number of cognitive functions and, noteworthy, with increased scores for ADHD in girls but not in boys.


Pyrethroid exposure in the first year of life was associated with decreased perceptual reasoning in rural children and with hyperactivity and ADHD predominantly in girls.


Keyword [en]
pyrethroids, children, pesticide, cognitive function, agriculture, behavior, neurodevelopment
National Category
Medical and Health Sciences
Research subject
Occupational and Environmental Medicine; Epidemiology
URN: urn:nbn:se:uu:diva-182162OAI: oai:DiVA.org:uu-182162DiVA: diva2:558614
Available from: 2012-10-04 Created: 2012-10-04 Last updated: 2012-10-29
In thesis
1. Environmental Pesticide Exposure and Neurobehavioral Effects among Children of Nicaraguan Agricultural Workers
Open this publication in new window or tab >>Environmental Pesticide Exposure and Neurobehavioral Effects among Children of Nicaraguan Agricultural Workers
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Background: Children exposed to pesticides are susceptible for neurodevelopmental disruption. Data from developing countries are scarce.

Aim: Assessing long-term and recent pesticide exposure in Nicaraguan children in relation to parental pesticide use and examining potential associated neurobehavioral effects.

Methods: In the first study, pre- and post-spraying urinary residues of the chlorpyrifos metabolite TCPY and diazinon metabolite IMPY were measured among 7 subsistence farmers and 10 plantation workers, and in one child per worker. In the second study, for 110 children in an agricultural village and 22 in a non-agricultural village, aged 7-9, parental pesticide use was assessed by hours of spraying and kilograms of active ingredients during pre-and-postnatal time windows, as proxies for children’s long term pesticide exposures. Urinary TCPY, 3-PBA (pyrethroid metabolite), and 2,4-D were determined in 211 samples of 74 children of the agricultural village. IQ components and total IQ (WISC-IV) were evaluated in all agricultural village children. Behavior was evaluated with the Conners’ Teacher Rating Scale-Revised: Short. Multivariate linear regression models assessed associations between long-term and recent exposure to organophosphates and pyrethroids and cognitive and behavioral scales.

Results: In study 1, post-spraying urinary levels of pesticide metabolites of subsistence farmers and their children were highly correlated (r=0.85), but not those of plantation workers and their children. In study 2, a wide range of exposures was reported by parents for all pesticides and time windows. The median urinary TCPY (3.7 μg/g creatinine), 3-PBA (2.8), and 2,4-D (0.9) were comparable to other studies for TCPY and 3-PBA but high for 2,4-D. Maximum levels were the highest reported for all compounds. Prenatal use of organophosphates affected working memory, and methamidophos also verbal comprehension and total IQ. Urinary TCPY was associated with poorer working memory. Organophosphate exposures were not associated with children’s behavior. Pyrethroid exposure during the first year of life associated with poorer perceptual reasoning and behavior, and urinary 3-PBA with a number of cognitive functions and ADHD in girls but not in boys.

Conclusion: Nicaraguan children in poor agricultural areas are highly exposed to pesticides, which is influenced by parental pesticide use in subsistence farms. Organophosphate and pyrethroid exposures adversely affect their neurobehavioral development.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 66 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 820
pesticides, organophosphates, pyrethroids, children, cognitive function, behavioral outcomes, neurodevelopment
National Category
Medical and Health Sciences
Research subject
Occupational and Environmental Medicine; Epidemiology
urn:nbn:se:uu:diva-182164 (URN)978-91-554-8488-0 (ISBN)
Public defence
2012-11-15, Frödingsalen, Ulleråkersvägen 40 A, Uppsala, 09:00 (English)
Available from: 2012-10-24 Created: 2012-10-04 Last updated: 2013-01-23

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Rodriguez, Teresa
By organisation
Department of Medical Sciences
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 310 hits
ReferencesLink to record
Permanent link

Direct link