Temporal Trends in Exposure to Organophosphate Flame Retardants in the United States.
During the past decade, use of organophosphate compounds as flame retardants and plasticizers has increased. Numerous studies investigating biomarkers (i.e., urinary metabolites) demonstrate ubiquitous human exposure and suggest that human exposure may be increasing. To formally assess temporal trends, we combined data from 14 U.S. epidemiologic studies for which our laboratory group previously assessed exposure to two commonly used organophosphate compounds, tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP). Using individual-level data and samples collected between 2002 and 2015, we assessed temporal and seasonal trends in urinary bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) and diphenyl phosphate (DPHP), the metabolites of TDCIPP and TPHP, respectively. Data suggest that BDCIPP concentrations have increased dramatically since 2002. Samples collected in 2014 and 2015 had BDCIPP concentrations that were more than 15 times higher than those collected in 2002 and 2003 (10β= 16.5; 95% confidence interval from 9.64 to 28.3). Our results also demonstrate significant increases in DPHP levels; however, increases were much smaller than for BDCIPP. Additionally, results suggest that exposure varies seasonally, with significantly higher levels of exposure in summer for both TDCIPP and TPHP. Given these increases, more research is needed to determine whether the levels of exposure experienced by the general population are related to adverse health outcomes.
Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.
Kate
K
Hoffman
Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.
Craig M
CM
Butt
Boston University School of Public Heath , Boston, Massachusetts 02118, United States.
Thomas F
TF
Webster
Boston University School of Public Heath , Boston, Massachusetts 02118, United States.
Emma V
EV
Preston
Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.
Stephanie C
SC
Hammel
Boston University School of Public Heath , Boston, Massachusetts 02118, United States.
Colleen
C
Makey
Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.
Amelia M
AM
Lorenzo
Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.
Ellen M
EM
Cooper
Harvard T. H. Chan School of Public Health , Boston, Massachusetts 02115, United States.
Courtney
C
Carignan
University of Michigan School of Public Health , Ann Arbor, Michigan 48109, United States.
John D
JD
Meeker
Harvard T. H. Chan School of Public Health , Boston, Massachusetts 02115, United States.
Russ
R
Hauser
Epidemiology Research Group, Department of Public Health and Primary Care, KU Leuven-University , B-3000 Leuven, Belgium.
Adelheid
A
Soubry
Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Duke University Medical Center, Durham, North Carolina 27710, United States; Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology, Duke University Medical Center, Durham, North Carolina 27710, United States.
Susan K
SK
Murphy
Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology, Duke University Medical Center , Durham, North Carolina 27710, United States.
Thomas M
TM
Price
Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina 27695, United States.
Cathrine
C
Hoyo
Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.
Emma
E
Mendelsohn
Environmental Working Group , Washington, D.C. 20009, United States.
Johanna
J
Congleton
Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States.
Julie L
JL
Daniels
Nicholas School of the Environment, Duke University , Durham, North Carolina 27708, United States.
Heather M
HM
Stapleton