Dataset Information

Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R Study.

ABSTRACT: The widespread use of organophosphate (OP) pesticides has resulted in ubiquitous exposure in humans, primarily through their diet. Exposure to OP pesticides may have adverse health effects, including neurobehavioral deficits in children. The optimal design of new studies requires data on the reliability of urinary measures of exposure. In the present study, urinary concentrations of six dialkyl phosphate (DAP) metabolites, the main urinary metabolites of OP pesticides, were determined in 120 pregnant women participating in the Generation R Study in Rotterdam. Intra-class correlation coefficients (ICCs) across serial urine specimens taken at <18, 18-25, and >25 weeks of pregnancy were determined to assess reliability. Geometric mean total DAP metabolite concentrations were 229 (GSD 2.2), 240 (GSD 2.1), and 224 (GSD 2.2)?nmol/g creatinine across the three periods of gestation. Metabolite concentrations from the serial urine specimens in general correlated moderately. The ICCs for the six DAP metabolites ranged from 0.14 to 0.38 (0.30 for total DAPs), indicating weak to moderate reliability. Although the DAP metabolite levels observed in this study are slightly higher and slightly more correlated than in previous studies, the low to moderate reliability indicates a high degree of within-person variability, which presents challenges for designing well-powered epidemiological studies.

SUBMITTER: Spaan S

PROVIDER: S-EPMC4409451 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature

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Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R Study.

Spaan Suzanne S Pronk Anjoeka A Koch Holger M HM Jusko Todd A TA Jaddoe Vincent W V VW Shaw Pamela A PA Tiemeier Henning M HM Hofman Albert A Pierik Frank H FH Longnecker Matthew P MP

Journal of exposure science & environmental epidemiology 20141217 3

The widespread use of organophosphate (OP) pesticides has resulted in ubiquitous exposure in humans, primarily through their diet. Exposure to OP pesticides may have adverse health effects, including neurobehavioral deficits in children. The optimal design of new studies requires data on the reliability of urinary measures of exposure. In the present study, urinary concentrations of six dialkyl phosphate (DAP) metabolites, the main urinary metabolites of OP pesticides, were determined in 120 pre ...[more]

PMID: 25515376

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Project description:BackgroundPrenatal exposure to organophosphate (OP) pesticides has been associated with altered neuronal cell development and behavioral changes in animal offspring. However, the few studies investigating the association between prenatal OP pesticide exposure and neurodevelopmental outcomes such as Attention-Deficit Hyperactivity Disorder (ADHD) and autistic traits in children produced mixed findings.ObjectiveThe objective of the present study was to examine whether maternal urinary concentrations of OP pesticide metabolites are associated with ADHD and autistic traits in children participating in the Generation R Study, a population-based birth cohort from Rotterdam, the Netherlands.MethodMaternal concentrations of 6 dialkylphosphates (DAPs) were measured using gas chromatography coupled with tandem mass spectrometry in urine samples collected at <18 weeks, 18-25 weeks, and > 25 weeks of gestation in 784 mother-child pairs. DAP metabolite concentrations were expressed as molar concentrations divided by creatinine levels and log10 transformed. ADHD traits were measured at ages 3, 6, and 10 years using the Child Behavior Checklist (CBCL) (n = 781) and autistic traits were measured at age 6 years using the Social Responsiveness Scale (SRS) (n = 622). First, regression models were fit for the averaged prenatal exposure across pregnancy. Second, we investigated associations for each collection phase separately, and applied a mutually adjusted model in which the effect of prenatal DAP concentrations from each time period on ADHD and autistic traits were jointly estimated. All associations were adjusted for relevant confounders.ResultsMedian DAP metabolite concentration was 309 nmol/g creatinine at <18 weeks, 316 nmol/g creatinine at 18-25 weeks, and 308 nmol/g creatinine at >25 weeks of gestation. Overall, DAP metabolite concentrations were not associated with ADHD traits. For instance, a log10 increase in averaged total DAP concentrations across gestation was not associated with a lower ADHD score (-0.03 per SD 95 CI: -0.28 to 0.23). Similarly, no associations between maternal DAP concentrations and autistic traits were detected.ConclusionsIn this study of maternal urinary DAP metabolite concentrations during pregnancy, we did not observe associations with ADHD and autistic traits in children. These are important null observations because of the relatively high background DAP concentrations across pregnancy, the relatively large sample size, and the 10-year follow-up of the offspring. Given the measurement error inherent in our OP pesticide exposure biomarkers, future studies using more urine samples are needed to accurately measure OP pesticide exposure over pregnancy in relation to ADHD and autistic traits.

Project description:Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers in consumer products, which contributes to widespread exposure of humans. OPE diester metabolites in urine have been used as biomarkers of human exposure to these chemicals. Little is known, however, about occurrence and temporal variability in urinary concentrations of OPE metabolites in humans. In this study, 11 OPE metabolites were measured in 213 urine samples collected from 19 volunteers from Albany, New York, United States, at 3-day intervals for five weeks to investigate temporal variability in urinary concentrations. Diphenyl phosphate (DPHP) and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) were the major OPE metabolites, detected in all urine samples at specific gravity (SG)-adjusted concentrations (geometric mean, GM) of 1060 and 414 pg/mL and creatinine (Cr)-adjusted concentration (GM) of 404 and 156 ng/g, respectively. Inter-day variability in urinary OPE metabolite concentrations in 19 individuals was evaluated by intraclass correlation coefficients (ICCs). The inter-day variability in Cr-adjusted OPE metabolite concentrations (ICC: 0.31-0.67) was lower than those of SG-adjusted (ICC: 0.19-0.71) and unadjusted urinary concentrations (ICC: 0.24-0.74). BDCIPP (ICC: 0.68) and bis(2-chloroethyl) phosphate (BCEP) (ICC: 0.67) concentrations showed a moderate-to-high reliability over the sampling period, whereas the other nine OPE metabolites exhibited a moderate reliability (ICC: 0.31-0.55). Urine samples were further stratified by gender, age, ethnicity, and body mass index (BMI). The concentrations of BDCIPP and DPHP were significantly lower in males with normal BMI (BMI: 18.5-25 kg/m2) than in females and other BMI categories (p < 0.01). Relatively high ICCs, indicating low inter-day variability, were observed for males (ICC: 0.35-0.71) of 30-40 years of age (ICC: 0.34-0.87) with normal BMI (ICC: 0.28-0.64). The daily exposure doses to OPEs were estimated from urinary concentrations of corresponding OPE metabolites. The estimated doses of triphenyl phosphate (TPHP) and triethyl phosphate (TEP), based on median urinary concentrations of their metabolites, were 19.4 and 24.0 ng/kg bw/day, and the exposure dose to ∑OPEs was estimated at 65.3 ng/kg bw/day. Overall, our results indicate a high ICC for Cr-adjusted urinary concentrations of 11 OPE metabolites in urine.

Project description:To monitor human exposure to pesticides, experts commonly measure their metabolites in urine, particularly dialkyl phosphates (DAPs), which include diethyl phosphate (DEP), Diethyl thiophosphate (DETP), diethyl dithiophosphate (DEDTP), dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP) and dimethyl dithiophosphate (DMDTP)to monitor the metabolites of organophosphates. These DAP metabolites are a urinary biomarker for assessing pesticide exposure and potential health risks. This study presented a new screening method combining ultrafast liquid chromatography with tandem mass spectrometry (UFLC-MS/MS) to detect six DAP metabolites in human urine. The study also compared standard sample extraction methods, namely, liquid-liquid extraction (LLE); quick, easy, cheap, effective, ruggedand safe (QuEChERS); and lyophilization. After a comprehensive analysis of the methods used to extract the analytes, including recovery rate, repeatability and reproducibility, the liquid-liquid extraction (LLE) method was found to be the best. It had a high recovery rate, was easy to handle, required less sample volume and had a short extraction time. Therefore, the LLE method was chosen for further analysis. The results showed excellent performance with high recoveries between 93% and 102%, precise repeatability (RSD) between 0.62% and 5.46% and acceptable reproducibility values (RSD) between 0.80% and 11.33%. The method also had limits of detection (LOD) ranging from 0.0201 ng/mL to 0.0697 ng/mL and limits of quantification (LOQ) ranging from 0.0609 ng/mL to 0.2112 ng/mL. Furthermore, the UFLC-MS/MS method was validated based on the SANTE guidance and successfully analyzed 150 urine samples from farmers and non-farmers. This validated method proved useful for biomonitoring studies focusing on OP pesticide exposure. It offers several advantages, such as a reduced need for samples, chemicals and materials, and a shorter analysis time. The method is sensitive and selective in detecting metabolites in human urine, making it a valuable approach for the practical and efficient assessment of pesticide exposure.

Project description:BackgroundEvidence from animal studies suggests that exposure to organophosphate flame retardants (PFRs) can disrupt endocrine function and impair embryo development. However, no epidemiologic studies have been conducted to evaluate effects on fertility and pregnancy outcomes.ObjectivesWe evaluated associations between urinary concentrations of PFR metabolites and outcomes of in vitro fertilization (IVF) treatment among couples recruited from an academic fertility clinic.MethodsThis analysis included 211 women enrolled in the Environment And Reproductive Health (EARTH) prospective cohort study (2005-2015) who provided one or two urine samples per IVF cycle. We measured five urinary PFR metabolites [bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), diphenyl phosphate (DPHP), isopropylphenyl phenyl phosphate (ip-PPP), tert-butylphenyl phenyl phosphate (tb-PPP), and bis(1-chloro-2-propyl) phosphate (BCIPP)] using negative electrospray ionization liquid chromatography tandem mass spectrometry (LC-MS/MS). Molar concentrations of the urinary PFR metabolites were summed. We used multivariable generalized linear mixed models to evaluate the association of the PFR metabolites with IVF outcomes, accounting for multiple IVF cycles per woman.ResultsDetection frequencies were high for BDCIPP (87%), DPHP (94%), and ip-PPP (80%), but low for tb-PPP (14%) and BCIPP (0%). We observed decreased success for several IVF outcomes across increasing quartiles of both summed and individual PFR metabolites (DPHP and ip-PPP) in our adjusted multivariable models. Significant declines in adjusted means from the lowest to highest quartile of ?PFR were observed for the proportion of cycles resulting in successful fertilization (10% decrease), implantation (31%), clinical pregnancy (41%), and live birth (38%).ConclusionsUsing IVF to investigate human reproduction and pregnancy outcomes, we found that concentrations of some urinary PFR metabolites were negatively associated with proportions of successful fertilization, implantation, clinical pregnancy, and live birth. https://doi.org/10.1289/EHP1021.

Project description:BACKGROUND:Use of organophosphate flame retardants (PFRs) has increased over the past decade following the phase out of some brominated flame retardants, leading to increased human exposure. We recently reported that increasing maternal PFR exposure is associated with poorer pregnancy outcomes among women from a fertility clinic. Because a small epidemiologic study previously reported an inverse association between male PFR exposures and sperm motility, we sought to examine associations of paternal urinary concentrations of PFR metabolites and their partner's pregnancy outcomes. METHODS:This analysis included 201 couples enrolled in the Environment and Reproductive Health (EARTH) prospective cohort study (2005-2015) who provided one or two urine samples per IVF cycle. In both the male and female partner, we measured five urinary PFR metabolites [bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), diphenyl phosphate (DPHP), isopropylphenyl phenyl phosphate (ip-PPP), tert-butylphenyl phenyl phosphate (tb-PPP) and bis(1-chloro-2-propyl) phosphate (BCIPP)] using negative electrospray ionization liquid chromatography tandem mass spectrometry (LC-MS/MS). The sum of the molar concentrations of the urinary PFR metabolites was calculated. We used multivariable generalized linear mixed models to evaluate the association of urinary concentrations of paternal PFR metabolites with IVF outcomes, accounting for multiple in vitro fertilization (IVF) cycles per couple. Models were adjusted for year of IVF treatment cycle, primary infertility diagnosis, and maternal urinary PFR metabolites as well as paternal and maternal age, body mass index, and race/ethnicity. RESULTS:Detection rates were high for paternal urinary concentrations of BDCIPP (84%), DPHP (87%) and ip-PPP (76%) but low for tb-PPP (12%) and zero for BCIPP (0%). We observed a significant 12% decline in the proportion of fertilized oocytes from the first to second quartile of male urinary ΣPFR and a 47% decline in the number of best quality embryos from the first to third quartile of male urinary BDCIPP in our adjusted models. An 8% decline in fertilization was observed for the highest compared to lowest quartile of urinary BDCIPP concentrations (95% CI: 0.01, 0.12, p-trend=0.06). CONCLUSIONS:Using IVF as a model to investigate human reproduction and pregnancy outcomes, we found that paternal urinary concentrations of BDCIPP were associated with reduced fertilization. In contrast to previously reported findings for the female partners, the paternal urinary PFR metabolites were not associated with the proportion of cycles resulting in successful implantation, clinical pregnancy, and live birth. These results indicate that paternal preconception exposure to TDCIPP may adversely impact successful oocyte fertilization, whereas female preconception exposure to ΣPFRs may be more relevant to adverse pregnancy outcomes.

Dataset Information

Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R Study.

Publications

Reliability of concentrations of organophosphate pesticide metabolites in serial urine specimens from pregnancy in the Generation R Study.

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