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Bibliography Tag: organophosphates

Bouchard et al., 2011

Bouchard MF, Chevrier J, Harley KG, Kogut K, Vedar M, Calderon N, Trujillo C, Johnson C, Bradman A, Barr DB, Eskenazi B., “Prenatal exposure to organophosphate pesticides and IQ in 7-year-old children.,” Environmental Health Perspectives, 2011, 119:8, DOI: 10.1289/ehp.1003185.

CONTEXT: Organophosphate (OP) pesticides are neurotoxic at high doses. Few studies have examined whether chronic exposure at lower levels could adversely affect children’s cognitive development.

OBJECTIVE: We examined associations between prenatal and postnatal exposure to OP pesticides and cognitive abilities in school-age children.

METHODS: We conducted a birth cohort study (Center for the Health Assessment of Mothers and Children of Salinas study) among predominantly Latino farmworker families from an agricultural community in California. We assessed exposure to OP pesticides by measuring dialkyl phosphate (DAP) metabolites in urine collected during pregnancy and from children at 6 months and 1, 2, 3.5, and 5 years of age. We administered the Wechsler Intelligence Scale for Children, 4th edition, to 329 children 7 years of age. Analyses were adjusted for maternal education and intelligence, Home Observation for Measurement of the Environment score, and language of cognitive assessment.

RESULTS: Urinary DAP concentrations measured during the first and second half of pregnancy had similar relations to cognitive scores, so we used the average of concentrations measured during pregnancy in further analyses. Averaged maternal DAP concentrations were associated with poorer scores for Working Memory, Processing Speed, Verbal Comprehension, Perceptual Reasoning, and Full-Scale intelligence quotient (IQ). Children in the highest quintile of maternal DAP concentrations had an average deficit of 7.0 IQ points compared with those in the lowest quintile. However, children’s urinary DAP concentrations were not consistently associated with cognitive scores.

CONCLUSIONS: Prenatal but not postnatal urinary DAP concentrations were associated with poorer intellectual development in 7-year-old children. Maternal urinary DAP concentrations in the present study were higher but nonetheless within the range of levels measured in the general U.S. population. FULL TEXT

Koureas et al., 2012

Koureas M, Tsakalof A, Tsatsakis A, Hadjichristodoulou C., “Systematic review of biomonitoring studies to determine the association between exposure to organophosphorus and pyrethroid insecticides and human health outcomes,” Toxicology Letters,  2012, 210:2, DOI: 10.1016/j.toxlet.2011.10.007.


For the appropriate protection of human health it is necessary to accurately estimate the health effects of human exposure to toxic compounds. In the present  review, epidemiological studies on the health effects of human exposure to organophosphorus  (OP) and pyrethroid (PYR) insecticides have been critically assessed. This review is focused on studies where the exposure assessment was based on quantification of specific biomarkers in urine or plasma. The 49 studies reviewed used different epidemiological approaches and analytical methods as well as different exposure assessment methodologies. With regard to OP pesticides, the studies reviewed suggested negative effects of prenatal exposure to these pesticides on neurodevelopment and male reproduction. Neurologic effects on adults, DNA damage and adverse birth outcomes were also associated with exposure to OP pesticides. With regard to exposure to PYR pesticides, there are currently few studies investigating the adverse health outcomes due to these pesticides. The effects studied in relation to PYR exposure were mainly male reproductive effects (sperm quality, sperm DNA damage and reproductive hormone disorders). Studies’ findings provided evidence to support the hypothesis that PYR exposure is adversely associated with effects on the male reproductive system. The validity of these epidemiological studies is strongly enhanced by exposure assessment based on biomarker quantification. However, for valid and reliable results and conclusions, attention should also be focused on the validity of the analytical methods used, study designs and the measured toxicants characteristics.

Eskenazi et al., 2004

Brenda Eskenazi, Kim Harley, Asa Bradman, Erin Weltzien, Nicholas P. Jewell, Dana B. Barr, Clement E. Furlong, and Nina T. Holland, “Association of in Utero Organophosphate Pesticide Exposure and Fetal Growth and Length of Gestation in an Agricultural Population,” Environmental Health Perspecitives, 112:10, 2004, DOI: 10.1289/ehp.6789


Although pesticide use is widespread, little is known about potential adverse health effects of in utero exposure. We investigated the effects of  organophosphate pesticide exposure during pregnancy on fetal growth and gestational duration in a cohort of low-income, Latina women living in an agricultural community in the Salinas Valley, California. We measured nonspecific metabolites of organophosphate pesticides (dimethyl and diethyl phosphates) and metabolites specific to malathion (malathion dicarboxylic acid), chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridinyl) phosphoro-thioate], and parathion (4-nitrophenol) in maternal urine collected twice during pregnancy. We also measured levels of cholinesterase in whole blood and butyryl cholinesterase in plasma in maternal and umbilical cord blood. We failed to demonstrate an adverse relationship between fetal growth and any measure of in utero organophosphate pesticide exposure. In fact, we found increases in body length and head circumference associated with some exposure measures.
However, we did find decreases in gestational duration associated with two measures of in utero pesticide exposure: urinary dimethyl phosphate metabolites [βadjusted = –0.41 weeks per log10 unit increase; 95% confidence interval (CI), –0.75––0.02; p = 0.02], which reflect exposure to dimethyl organophosphate compounds such as malathion, and umbilical cord cholinesterase (βadjusted = 0.34 weeks per unit increase; 95% CI, 0.13–0.55; p = 0.001). Shortened gestational duration was most clearly related to increasing exposure levels in the latter part of pregnancy. These associations with gestational age may be biologically plausible given that organophosphate pesticides depress cholinesterase and acetylcholine stimulates contraction of the uterus. However, despite these observed associations, the rate of preterm delivery in this population (6.4%) was lower than in a U.S. reference population.   FULL TEXT

Ranjbar et al., 2015

Mahsa Ranjbar, Michael A. Rotondi, Chris I. Ardern, and Jennifer L. Kuk, “The Influence of Urinary Concentrations of Organophosphate Metabolites on the Relationship between BMI and Cardiometabolic Health Risk,” Journal of Obesity, 2015, DOI: 10.1155/2015/687914


The objective was to determine whether detectable levels of OP metabolites influence the relationship between BMI and cardiometabolic health. This cross-sectional study was conducted using 2227 adults from the 1999–2008 NHANES datasets.  Urinary concentrations of six dialkyl phosphate metabolites were dichotomized to above and below the detection limit. Weighted multiple regression analysis was performed adjusting for confounding variables. Independent of BMI, individuals with detectable metabolites had higher diastolic blood pressure (for dimethylphosphate, diethylphosphate, and diethyldithiophosphate; ???? < 0.05), lower HDL (for diethyldithiophosphate; ???? = 0.02), and higher triglyceride (for dimethyldithiophosphate; ???? = 0.05) than those below detection. Contrarily, those with detectable dimethylthiophosphate had better LDL, HDL, and total cholesterol, independent of BMI. Individuals at a higher BMI range who had detectable diethylphosphate (interaction: ???? = 0.03) and diethylthiophosphate (interaction: ???? = 0.02) exhibited lower HDL, while little difference existed between OP metabolite detection statuses at lower BMIs.  Similarly, individuals with high BMIs and detectable diethylphosphate had higher triglyceride than those without detectable levels, while minimal differences between diethylphosphate detection statuses were observed at lower BMIs (interaction: ???? = 0.02). Thus, cardiometabolic health outcome differs depending on the specific OP metabolite being examined, with higher BMIs amplifying health risk.  FULL TEXT

Omoike et al., 2015

Omoike OE, Lewis RC, Meeker JD, “Association between urinary biomarkers of exposure to organophosphate insecticides and serum reproductive hormones in men from NHANES 1999-2002,” Reproductive Toxicology, 2015, 53, DOI: 10.1016/j.reprotox.2015.04.005.

ABSTRACT: Exposure to organophosphate (OP) insecticides may alter reproductive hormone levels in men and increase the risk for poor reductive health and other adverse health outcomes. However, relevant epidemiology studies in men are limited. We evaluated urinary concentrations of OP metabolites (3,5,6-trichloro-2-pyridinol and six dialkyl phosphates) in relation to serum concentrations of testosterone (T) and estradiol among 356 men aged 20-55 years old from the U.S. National Health and Nutrition Examination Survey. Biomarkers were detected in greater than 50% of the samples, except for diethyldithiophosphate, dimethylphosphate, and dimethyldithiophosphate. In adjusted regression models, we observed a statistically significant inverse relationship between diethyl phosphate (DEP) and T when DEP was modeled as either a continuous or categorical variable. These findings add to the limited evidence that exposure to certain OP insecticides is linked to altered T in men, which may have important implications for male health.  FULL TEXT

Lewis et al., 2015

Lewis RC, Cantonwine DE, Del Toro LV, Calafat AM, Valentin-Blasini L, Davis MD, Montesano MA, Alshawabkeh AN, Cordero JF, Meeker JD, “Distribution and determinants of urinary biomarkers of exposure to organophosphate insecticides in Puerto Rican pregnant women,” The Science of the Total Environment, 2015, 512-513:337-44, DOI: 10.1016/j.scitotenv.2015.01.059.


Globally, human exposures to organophosphate (OP) insecticides may pose a significant burden to the health of mothers and their developing fetuses. Unfortunately, relevant data is limited in certain areas of the world concerning sources of exposure to OP insecticides in pregnant populations. To begin to address this gap in information for Puerto Rico, we studied repeated measures of urinary concentrations of 10 OP insecticide metabolites among 54 pregnant women from the northern karst region of the island. We also collected demographic data and self-reported information on the consumption of fruits, vegetables, and legumes in the past 48 h before urine collection and home pest-related issues. We calculated the distributions of the urinary biomarkers and compared them to women of reproductive age from the general U.S. population. We also used statistical models accounting for correlated data to assess within-subject temporal variability of the urinary biomarkers and to identify predictors of exposure. We found that for all but two metabolites (para-nitrophenol [PNP], diethylthiophosphate [DETP]), 50th or 95th percentile urinary concentrations (the metric that was used for comparison was based on the biomarker’s detection frequency) of the other eight metabolites (3,5,6-trichloro-2-pyridinol [TCPY], 2-isopropyl-4-methyl-6-hydroxy-pyrimidine, malathion dicarboxylic acid, diethylphosphate, diethyldithiophosphate, dimethylphosphate, dimethylthiophosphate [DMTP], dimethyldithiophosphate) were somewhat lower in our cohort compared with similarly aged women from the continental United States. TCPY, PNP, DETP, and DMTP, which were the only urinary metabolites detected in greater than 50% of the samples, had poor reproducibility (intraclass correlation coefficient range: 0.19-0.28) during pregnancy. Positive predictors of OP insecticide exposure included: age; marital or employment status; consumption of cherries, grape juice, peanuts, peanut butter, or raisins; and residential application of pesticides. Further research is needed to understand what aspects of the predictors identified influence OP insecticide exposure during pregnancy. FULL TEXT

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