Variability of organophosphorous pesticide metabolite levels in spot and 24-hr urine samples collected from young children during 1 week.

dc.contributor.authorBradman, Asa
dc.contributor.authorKogut, Katherine
dc.contributor.authorEisen, Ellen A.
dc.contributor.authorJewell, Nicholas
dc.contributor.authorQuiros-Alcala, Lesliam
dc.contributor.authorCastorina, Rosemary
dc.contributor.authorChevrier, Jonathan
dc.contributor.authorHolland, Nina T.
dc.contributor.authorBarr, Dana B.
dc.contributor.authorKavanagh-Baird, Gerry
dc.contributor.authorEskenazi, Brenda
dc.date.accessioned2016-11-11T18:57:05Z
dc.date.available2016-11-11T18:57:05Z
dc.date.issued2013-01
dc.description.abstractBackground: Dialkyl phosphate (DAP) metabolites in spot urine samples are frequently used to characterize children’s exposures to organophosphorous (OP) pesticides. However, variable exposure and short biological half-lives of OP pesticides could result in highly variable measurements, leading to exposure misclassification. Objective: We examined within- and between-child variability in DAP metabolites in urine samples collected during 1 week. Methods: We collected spot urine samples over 7 consecutive days from 25 children (3–6 years of age). On two of the days, we collected 24-hr voids. We assessed the reproducibility of urinary DAP metabolite concentrations and evaluated the sensitivity and specificity of spot urine samples as predictors of high (top 20%) or elevated (top 40%) weekly average DAP metabolite concentrations. Results: Within-child variance exceeded between-child variance by a factor of two to eight, depending on metabolite grouping. Although total DAP concentrations in single spot urine samples were moderately to strongly associated with concentrations in same-day 24-hr samples (r ≈ 0.6–0.8, p < 0.01), concentrations in spot samples collected > 1 day apart and in 24-hr samples collected 3 days apart were weakly correlated (r ≈ –0.21 to 0.38). Single spot samples predicted high (top 20%) and elevated (top 40%) full-week average total DAP excretion with only moderate sensitivity (≈ 0.52 and ≈ 0.67, respectively) but relatively high specificity (≈ 0.88 and ≈ 0.78, respectively). Conclusions: The high variability we observed in children’s DAP metabolite concentrations suggests that single-day urine samples provide only a brief snapshot of exposure. Sensitivity analyses suggest that classification of cumulative OP exposure based on spot samples is prone to type 2 classification errors.en_US
dc.description.sponsorshipThis research was supported by grant numbers RD 83171001 and RD 876709 from the U.S. Environmental Protection Agency (EPA), and PO1 ES009605 from the National Institute of Environmental Health Sciences (NIEHS).en_US
dc.identifierhttps://doi.org/10.13016/M24F8D
dc.identifier.citationBradman A, Kogut K, Eisen EA, Jewell NP, Quiros-Alcala L, Castorina R, Chevrier J, Holland NT, Barr DB, Kavanagh-Baird G, and Eskenazi B. Variability of organophosphorous pesticide metabolite levels in spot and 24-hr urine samples collected from young children during 1 week. Environmental health perspectives. 2013;121(1):118-24.http://dx.doi.org/10.1289/ehp.1104808en_US
dc.identifier.urihttp://hdl.handle.net/1903/18876
dc.language.isoen_USen_US
dc.relation.isAvailableAtSchool of Public Health
dc.relation.isAvailableAtMaryland Institute of Applied Environmental Health
dc.relation.isAvailableAtDigital Repository at the University of Maryland
dc.relation.isAvailableAtUniversity of Maryland (College Park, Md)
dc.subjectbiomarkersen_US
dc.subjectchildren
dc.subjectexposure
dc.subjectmetabolites
dc.subjectorganophosphorous
dc.subjectpesticides
dc.subjecturine
dc.subjectvariability
dc.titleVariability of organophosphorous pesticide metabolite levels in spot and 24-hr urine samples collected from young children during 1 week.en_US
dc.typeArticleen_US

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