title: Limitations on the uses of multimedia exposure measurements for multipathway exposure assessment--Part I: Handling observations below detection limits.
abstract: Multimedia data from two probability-based exposure studies were investigated in terms of how censoring of nondetects affected estimation of population parameters and associations. Appropriate methods for handling censored below-detection-limit(BDL)values in this context were unclear since sampling weights were involved and since bivariate associations/measures were of interest. Both simple substitution(e.g., using 1/2 or 2/3 of the detection limit(DL)for BDL values)and truncation-based strategies were investigated by creating some artificial DLs and comparing resultant estimates with the original studies'uncensored results. The substitution methods generally outperformed the truncation methods, with the(2/3)DL substitution generally performing best.
authors.affiliation: RTI International, PO Box 12194, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA. clayton@rti.org
authors.forename: C Andrew
authors.initials: CA
authors.lastname: Clayton
authors.forename: Paul L
authors.initials: PL
authors.lastname: Mosquin
authors.forename: Edo D
authors.initials: ED
authors.lastname: Pellizzari
authors.forename: James J
authors.initials: JJ
authors.lastname: Quackenboss
mesh_terms: D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D004781:Environmental Exposure; D006801:Humans; D006838:Hydrocarbons / Q000032:analysis*; D008670:Metals / Q000032:analysis*; D019212:Multimedia; D010755:Organophosphates / Q000032:analysis*; D011159:Population Surveillance / Q000379:methods; D014481:United States; D014484:United States Environmental Protection Agency
chemical_list: D006838:Hydrocarbons; D008670:Metals; D010755:Organophosphates