title: Impacts of geocoding uncertainty on reconstructed PFOA exposures and their epidemiological association with preeclampsia.
abstract: Many epidemiology studies have investigated associations of perfluorooctanoate (PFOA) exposures with a variety of adverse health outcomes for participants in the C8 Health Project. The exposure concentrations (i.e., air and groundwater) used in these studies were determined primarily based on participant's residential locations. However, for residential addresses that could not be geocoded to the street level, the exposure concentrations were assigned based on population-weighted ZIP code centroid, which may result in exposure mischaracterization. The aim of this current study is to evaluate the potential impact of mischaracterized exposure concentrations due to geocoding uncertainty on the predicted serum PFOA concentrations and the epidemiological association between PFOA exposure and preeclampsia. For both workplace addresses and incompletely geocoded residential addresses, we used Monte Carlo (MC) simulation to assign alternate geographic locations within the reported ZIP code (instead of population-weighted ZIP code centroids) and the corresponding exposure concentrations. We found that mischaracterization of residential exposure due to population-weighted ZIP code centroid assignment had no significant impact on the serum PFOA concentration predictions and the epidemiological association of PFOA exposure with preeclampsia. In contrast, the uncertainty in workplace exposure moderately impacted the rank exposure among the participants. We observed a 41% increase in the average adjusted odds ratio of preeclampsia occurrence that may be due to differing proportions of cases (64.3%) and controls (54.5%) with workplace address geocodes during pregnancy. This finding suggests that differential exposure mischaracterization can be reduced by obtaining accurate exposure information such as street addresses and tap water consumption, for both workplaces and residences. The analysis we present is one approach for estimating the potential impacts of positional errors in a geocoding-based exposure assessment on exposure estimates and epidemiological study results.
authors: Environmental Health Sciences Graduate Program, 2032, AIRB, University of California, Irvine, CA 92697-3957, USA; ICF International. Fairfax, Virginia, USA. Electronic address: ragaavanasi@gmail.com.
authors: Raghavendhran
authors: R
authors: Avanasi
authors: Department of Public Health Sciences, One Shields Avenue, MS1-C, Davis, CA 95616-8638, USA.
authors: Hyeong-Moo
authors: HM
authors: Shin
authors: Environmental Health Sciences Graduate Program, 2032, AIRB, University of California, Irvine, CA 92697-3957, USA; Program in Public Health, AIRB, University of California, Irvine, CA 92697-3957, USA.
authors: Veronica M
authors: VM
authors: Vieira
authors: Environmental Health Sciences Graduate Program, 2032, AIRB, University of California, Irvine, CA 92697-3957, USA; Program in Public Health, AIRB, University of California, Irvine, CA 92697-3957, USA; Department of Statistics and Department of Epidemiology, University of California, Irvine, CA, USA.
authors: Scott M
authors: SM
authors: Bartell
mesh_terms: D002210:Caprylates / Q000097:blood / Q000633:toxicity*; D005260:Female; D005466:Fluorocarbons / Q000097:blood / Q000633:toxicity*; D062305:Geographic Mapping; D006801:Humans; D009010:Monte Carlo Method; D009820:Ohio / Q000453:epidemiology; D011225:Pre-Eclampsia / Q000139:chemically induced* / Q000453:epidemiology*; D011247:Pregnancy; D035501:Uncertainty; D014903:West Virginia / Q000453:epidemiology
chemical_list: D002210:Caprylates; D005466:Fluorocarbons; C023036:perfluorooctanoic acid
keywords: C8 Health Project; Differential exposure mischaracterization; Geocoding uncertainty; Perfluorooctanoate; Preeclampsia