Boris Lucero

Neurodevelopmental effects in children associated with exposure to organophosphate pesticides: A systematic review

Many studies have investigated the neurodevelopmental effects of prenatal and early childhood exposures to organophosphate (OP) pesticides among children, but they have not been collectively evaluated. The aim of the present article is to synthesize reported evidence over the last decade on OP exposure and neurodevelopmental effects in children. The Data Sources were PubMed, Web of Science, EBSCO, SciVerse Scopus, SpringerLink, SciELO and DOAJ. The eligibility criteria considered were studies assessing exposure to OP pesticides and neurodevelopmental effects in children from birth to 18 years of age, published between 2002 and 2012 in English or Spanish. Twenty-seven articles met the eligibility criteria. Studies were rated for evidential consideration as high, intermediate, or low based upon the study design, number of participants, exposure measurement, and neurodevelopmental measures. All but one of the 27 studies evaluated showed some negative effects of pesticides on neurobehavioral development. A positive dose-response relationship between OP exposure and neurodevelopmental outcomes was found in all but one of the 12 studies that assessed dose-response. In the ten longitudinal studies that assessed prenatal exposure to OPs, cognitive deficits (related to working memory) were found in children at age 7 years, behavioral deficits (related to attention) seen mainly in toddlers, and motor deficits (abnormal reflexes) seen mainly in neonates. No meta-analysis was possible due to different measurements of exposure assessment and outcomes. Eleven studies (all longitudinal) were rated high, 14 studies were rated intermediate, and two studies were rated low. Evidence of neurological deficits associated with exposure to OP pesticides in children is growing. The studies reviewed collectively support the hypothesis that exposure to OP pesticides induces neurotoxic effects. Further research is needed to understand effects associated with exposure in critical windows of development.

Predictors of exposure to organophosphate pesticides in schoolchildren in the Province of Talca, Chile

BACKGROUND Few data exist in Latin America concerning the association between organophosphate (OP) urinary metabolites and the consumption of fruits and vegetables and other exposure risk variables in schoolchildren. METHODS We collected samples of urine from 190 Chilean children aged 6-12 years, fruits and vegetables, water and soil from schools and homes, and sociodemographic data through a questionnaire. We measured urinary dialkylphosphate (DAP) OP metabolites and OP pesticide residues in food consumed by these 190 children during two seasons: December 2010 (summer) and May 2011 (fall). We analyzed the relationship between urinary DAP concentrations and pesticide residues in food, home pesticide use, and residential location. RESULTS Diethylalkylphosphates (DEAP) and dimethylalkylphosphates (DMAP) were detected in urine in 76% and 27% of the samples, respectively. Factors associated with urinary DEAP included chlorpyrifos in consumed fruits (p<0.0001), urinary creatinine (p<0.0001), rural residence (p=0.02) and age less than 9 years (p=0.004). Factors associated with urinary DMAP included the presence of phosmet residues in fruits (p<0.0001), close proximity to a farm (p=0.002), home fenitrothion use (p=0.009), and season (p<0.0001). CONCLUSIONS Urinary DAP levels in Chilean school children were high compared to previously reported studies. The presence of chlorpyrifos and phosmet residues in fruits was the major factor predicting urinary DAP metabolite concentrations in children.

Chronic exposure to organophosphate (OP) pesticides and neuropsychological functioning in farm workers: a review

Background: Previous studies have demonstrated that acute poisoning from exposure to organophosphate (OP) pesticides in agricultural workers causes adverse health effects. However, neuropsychological and cognitive effects of chronic occupational exposure to OP pesticides remain controversial. Objective: To identify, evaluate, and systematize existing evidence regarding chronic exposure to OP pesticides and neuropsychological effects in farmworkers. Methods: Using the PubMed search engine, a systematic review process was implemented and replicated according to the PRISMA statement. Eligibility criteria included workers over 18 years of age exposed to OP pesticides as well as assessment of neuropsychological and cognitive functioning. Search terms were in English and Spanish languages and included organophosphate and workers. Results: Of the search results, 33 of 1,256 articles meet eligibility criteria. Twenty-four studies found an association between chronic occupational exposure to OP pesticides and low neuropsychological performance in workers. We classified nine of the studies to have study design limitations. Studies indicated occupational exposure to OP pesticides is linked to difficulties in executive functions, psychomotor speed, verbal, memory, attention, processing speed, visual–spatial functioning, and coordination. Nine studies find no relationship between OP pesticides exposure and neuropsychological performance. Conclusions: Overall, evidence suggests an association between chronic occupational exposure to OP pesticides and neuropsychological effects. However, there is no consensus about the specific cognitive skills affected.

Efectos de los gestos icónicos en la memoria de trabajo de estudiantes con discapacidad intelectual leve

Resumen Se presentan los resultados de un estudio sobre la influencia del gesto icónico en la memoria de trabajo en estudiantes con discapacidad intelectual leve. Cómo hipótesis general se planteó que la retención de la información verbal en la memoria de trabajo variaría en función del uso de gestos en niños/as con discapacidad intelectual leve, donde el gesto congruente con la expresión verbal facilitaría dichos procesos de memoria. Vara probarlo, se realizó un estudio experimental con 120 niños/as con discapacidad intelectual leve, que asistían al nivel básico en escuelas especiales y de plan común. Los resultados indican la existencia de diferencias significativas (p < 0.05) en el recuerdo inmediato del gesto asociado al discurso verbal. Los niños recordaban más palabras y frases si se presentaba un gesto congruente. Se concluyó que los gestos congruentes facilitan las tareas de memoria, considerándose crucial el lenguaje no verbal en los contextos de aprendizaje.

Urinary Inorganic Arsenic Concentration and Gestational Diabetes Mellitus in Pregnant Women from Arica, Chile

Introduction: The association of total arsenic exposure with impaired glucose tolerance and gestational diabetes has been shown; however, evidence regarding urinary inorganic arsenic in pregnant women is still limited. Our aim was to evaluate the association between urinary inorganic arsenic concentration and gestational diabetes among pregnant women living in Arica, Chile. Methods: Cross-sectional study of pregnant women receiving care at primary health centers in urban Arica. The exposure was urinary inorganic arsenic concentration, while gestational diabetes was the outcome. The association was evaluated using multiple logistic regression models adjusted by age, education level, ethnicity, and pre-pregnancy body mass index. Results: 244 pregnant women were surveyed. The median urinary inorganic arsenic was 14.95 μg/L, and the prevalence of gestational diabetes was 8.6%. After adjusting, we did not find a significant association between gestational diabetes and inorganic arsenic exposure tertiles (Odds ratio (OR) 2.98, 95% CI = 0.87–10.18), (OR 1.07, 95% CI = 0.26–4.33). Conclusion: This study did not provide evidence on the relationship between urinary inorganic arsenic concentration and gestational diabetes. Further research is needed to elucidate the factors underlying this association.

Reliability and factorial validity of a questionnaire to assess organophosphate pesticide exposure to agricultural workers in Maule, Chile

ABSTRACT The aim was to evaluate the reliability and validity of a questionnaire to assess organophosphate pesticide (OP) exposure in agricultural workers. We then enrolled a random sample of 114 agricultural workers from the region of Maule, Chile (mean age = 50 years [SD = 12]). An internal consistency analysis (Cronbach’s alpha> 0.70) and a Varimax rotational factorial analysis were applied. The instrument had a high reliability to predict likely occupational pesticide exposures: Cronbach’s alpha = 0.95, the Kaiser–Meyer–Olkin (KMO) measure was 0.90 and the Bartell sphericity test = p < 0.001. Four factors explaining 68% of the variance were extracted. The factors identified were as follows: (1) labor conditions during application of OPs; (2) use of personal protective equipment; (3) workplace conditions related to OP exposure and (4) home conditions related to OP exposure. The questionnaire has adequate metric properties to characterize likely OP exposure of agricultural workers and to explore associated working and home conditions.