title: Changes in persistent organic pollutant levels from adolescence to young adulthood.
abstract: Elimination rates and their corresponding half-lives are conceptually important and intuitively accessible pharmacokinetic measures of toxicant elimination, but regression-based estimates are biased proportional to the degree of continuing (background) exposure. We propose an alternative estimator, the censored normal regression model, which uses all observations, but treats individuals whose initial level failed to exceed their follow-up level as censored observations to weight the regression estimates from those that declined between blood draws. In this manner, we derive the intrinsic elimination rate, the elimination rate free from ongoing exposure, as a parameter in a regression with an unobserved, latent dependent variable. We utilize sequential measurements of persistent organic pollutants (POPs) levels from adolescence to adulthood, a period of intense change in size and body composition, to quantify individual-level change within a community exposed to significant quantities of contaminants over an extended period of time. Although much research has been conducted on effects of POPs, far less attention has been given to vectors of intake and changes in toxicant levels during the life course. We apply exploratory factor analysis (EFA) to types and timing of consumption, along with physical behavioral characteristics, to identify a structure of seven underlying factors. Although several variables show factorial complexity, the latent constructs included an age/maturation and period-related factor, a nutritional composite, consumption prior to pregnancy, fish and fowl consumed during pregnancy, factors distinguishing body mass and weight from height, and bottom-feeding fish consumption. Unadjusted and adjusted half-lives using the censored normal regression estimator, as well as estimated half-lives from conventional log concentration regressions, are reported for PCB groupings, specific congeners, p,p'-DDE, and HCB.
authors: University at Albany, Department of Anthropology, A&S 237, 1400 Washington Avenue, Albany, NY, USA; Center for the Elimination of Minority Health Disparities, University at Albany-SUNY, 1400 Washington Avenue, Albany, NY, USA. Electronic address: mvgallo@albany.edu.
authors: Mia V
authors: MV
authors: Gallo
authors: University at Albany, Department of Sociology, A&S 339, 1400 Washington Avenue, Albany, NY, USA.
authors: Glenn D
authors: GD
authors: Deane
authors: Florida International University, Department of Chemistry & Biochemistry, 11200S.W. 8th St., Miami, FL, USA.
authors: Anthony P
authors: AP
authors: DeCaprio
authors: University at Albany, Department of Anthropology, A&S 237, 1400 Washington Avenue, Albany, NY, USA; Center for the Elimination of Minority Health Disparities, University at Albany-SUNY, 1400 Washington Avenue, Albany, NY, USA; University at Albany, Department of Epidemiology and Biostatistics, School of Public Health One University Place, Room 131, Rensselaer, NY, USA.
authors: Lawrence M
authors: LM
authors: Schell
mesh_terms: D000293:Adolescent; D000328:Adult; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000032:analysis* / Q000493:pharmacokinetics / Q000633:toxicity; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D009930:Organic Chemicals / Q000032:analysis* / Q000493:pharmacokinetics / Q000633:toxicity; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D009930:Organic Chemicals
keywords: DDT; HCB; Hexachlorobenzene; Mohawk; Native American; PCBs; POPs; Persistent organic pollutants; Polychlorinated biphenyls; p,p'-DDE; p,p′-dichlorophenyldichloroethylene