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Review
. 2015 Dec:85:27-39.
doi: 10.1016/j.envint.2015.08.005. Epub 2015 Aug 24.

Exposure assessment issues in epidemiology studies of phthalates

Lauren E Johns  1 , Glinda S Cooper  2 , Audrey Galizia  3 , John D Meeker  4
Affiliations
Review

Exposure assessment issues in epidemiology studies of phthalates

Lauren E Johns et al. Environ Int. 2015 Dec.

Abstract

Purpose: The purpose of this paper is to review exposure assessment issues that need to be addressed in designing and interpreting epidemiology studies of phthalates, a class of chemicals commonly used in consumer and personal care products. Specific issues include population trends in exposure, temporal reliability of a urinary metabolite measurement, and how well a single urine sample may represent longer-term exposure. The focus of this review is on seven specific phthalates: diethyl phthalate (DEP); di-n-butyl phthalate (DBP); diisobutyl phthalate (DiBP); butyl benzyl phthalate (BBzP); di(2-ethylhexyl) phthalate (DEHP); diisononyl phthalate (DiNP); and diisodecyl phthalate (DiDP).

Methods: Comprehensive literature search using multiple search strategies.

Results: Since 2001, declines in population exposure to DEP, BBzP, DBP, and DEHP have been reported in the United States and Germany, but DEHP exposure has increased in China. Although the half-lives of various phthalate metabolites are relatively short (3 to 18h), the intraclass correlation coefficients (ICCs) for phthalate metabolites, based on spot and first morning urine samples collected over a week to several months, range from weak to moderate, with a tendency toward higher ICCs (greater temporal stability) for metabolites of the shorter-chained (DEP, DBP, DiBP and BBzP, ICCs generally 0.3 to 0.6) compared with those of the longer-chained (DEHP, DiNP, DiDP, ICCs generally 0.1 to 0.3) phthalates. Additional research on optimal approaches to addressing the issue of urine dilution in studies of associations between biomarkers and different type of health effects is needed.

Conclusions: In conclusion, the measurement of urinary metabolite concentrations in urine could serve as a valuable approach to estimating exposure to phthalates in environmental epidemiology studies. Careful consideration of the strengths and limitations of this approach when interpreting study results is required.

Keywords: Biomarkers; Biomonitoring; Environmental epidemiology; Exposure assessment; Metabolites; Phthalates; Temporal reliability; Trends.

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Figures

Figure 1
Figure 1
Intraclass correlation coefficients (ICC) based on repeated spot or first morning urine samples by sampling time for phthalate metabolites of DBP (MBP), DiBP (MiBP), BBzP (MBzP), and DEP (MEP).
Figure 2
Figure 2
Intraclass correlation coefficients (ICC) based on repeated spot or first morning urine samples by sampling time for phthalate metabolites of DEHP (MEHP, MEOHP, and summed metabolites) and DINP (MCOP, MINP, and summed metabolites)
See this image and copyright information in PMC

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