Reproducibility of urinary phthalate metabolites in first morning urine samples.

Abstract

Phthalates are ubiquitous in our modern environment because of their use in plastics and cosmetic products. Phthalate monoesters--primarily monoethylhexyl phthalate and monobutyl phthalate--are reproductive and developmental toxicants in animals. Accurate measures of phthalate exposure are needed to assess their human health effects. Phthalate monoesters have a biologic half-life of approximately 12 hr, and little is known about the temporal variability and daily reproducibility of urinary measures in humans. To explore these aspects, we measured seven phthalate monoesters and creatinine concentration in two consecutive first-morning urine specimens from 46 African-American women, ages 35-49 years, residing in the Washington, DC, area in 1996-1997. We measured phthalate monoesters using high-pressure liquid chromatography followed by tandem mass spectrometry on a triple quadrupole instrument using atmospheric pressure chemical ionization. We detected four phthalate monoesters in all subjects, with median levels of 31 ng/mL for monobenzyl phthalate (mBzP), 53 ng/mL for monobutyl phthalate (mBP), 211 ng/mL for monoethyl phthalate (mEP), and 7.3 ng/mL for monoethylhexyl phthalate (mEHP). These were similar to concentrations reported for other populations using spot urine specimens. Phthalate levels did not differ between the two sampling days. The Pearson correlation coefficient between the concentrations on the 2 days was 0.8 for mBP, 0.7 for mEHP, 0.6 for mEP, and 0.5 for mBzP. These results suggest that even with the short half-lives of phthalates, women's patterns of exposure may be sufficiently stable to assign an exposure level based on a single first morning void urine measurement.

Exposure assessment of phthalate esters in Japanese pregnant women by using urinary metabolite analysis

“…This may be related to the much lower production of DEP in Japan (700 tons in 2002 [35]) than in the USA (11,700 tons in 1988 [2]). On the contrary, urinary MnBP concentration was higher in the present study and in European countries [14,36] than in the USA, except for Hoppin et al's [18] study. However, production of DBP was 4,135 tons in Japan [35] and 7,752 tons in USA [3], thus it is unlikely that the difference in MnBP concentration between countries was related to production amount of DBP.…”

“…Although single spot urine sample was usually used for exposure assessment [7,[13][14][15][16][17], concern has been raised over whether monoester concentration in single spot urine represents the subject's long-term exposure to phthalate esters because biological half-life in human body is short. Hoppin et al [18], Hauser et al [19], and Teitelbaum et al [20] reported utility of single spot urine for phthalate esters exposure assessment; however, Fromme et al [21] did not. Hence it is still unclear whether spot urine is usable for human exposure assessment of phthalate esters.…”

Estimated daily intake of phthalates in occupationally exposed groups

“…Temporal variability in metabolite concentrations is further heightened by the metabolites' relatively short half-lives and rapid elimination in the urine (Anderson et al, 2001;Api, 2001;Koch et al, 2005aKoch et al, , 2004. Within-person variability in urinary phthalate metabolite concentrations has been shown to depend on the population, phthalate metabolite, and time frame of interest (Hoppin et al, 2002;Hauser et al, 2004;Fromme et al, 2007;Teitelbaum et al, 2008). The degree of temporal variability has implications for using a single urine sample to predict phthalate exposures over a specified time.…”

Reproductive outcome in a cohort of male and female rubber workers: a registry study

“…Experimentally, diethylnitrosamine has been shown to be hormonally active (Liao et al 2001), as well as phthalates (Hoppin et al 2002). There is evidence from animal data that phthalates have adverse reproductive eVects in males (Foeter et al 2001;Gray et al 2000;Mylchreest et al 2002;Nagao et al 2000), and possibly also females (Ema and Miyawaki 2001).…”