| Temporal Variability of Urinary Phthalate Metabolite Levels in Men of Reproductive Age Russ Hauser,1,2 John D. Meeker,1 Sohee Park,3 Manori J. Silva,4 and Antonia M. Calafat4 1Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA; 2Vincent Memorial Obstetrics and Gynecology Service, Andrology Laboratory and In Vitro Fertilization Unit, Massachusetts General Hospital, Boston, Massachusetts, USA; 3Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA; 4National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA Abstract
Phthalates are a family of multifunctional chemicals widely used in personal care and other consumer products. The ubiquitous use of phthalates results in human exposure through multiple sources and routes, including dietary ingestion, dermal absorption, inhalation, and parenteral exposure from medical devices containing phthalates. We explored the temporal variability over 3 months in urinary phthalate metabolite levels among 11 men who collected up to nine urine samples each during this time period. Eight phthalate metabolites were measured by solid-phase extraction-high-performance liquid chromatography-tandem mass spectrometry. Statistical analyses were performed to determine the between- and within-subject variance apportionment, and the sensitivity and specificity of a single urine sample to classify a subject's 3-month average exposure. Five of the eight phthalates were frequently detected. Monoethyl phthalate (MEP) was detected in 100% of samples ; monobutyl phthalate, monobenzyl phthalate, mono-2-ethylhexyl phthalate (MEHP) , and monomethyl phthalate were detected in > 90% of samples. Although we found both substantial day-to-day and month-to-month variability in each individual's urinary phthalate metabolite levels, a single urine sample was moderately predictive of each subject's exposure over 3 months. The sensitivities ranged from 0.56 to 0.74. Both the degree of between- and within-subject variance and the predictive ability of a single urine sample differed among phthalate metabolites. In particular, a single urine sample was most predictive for MEP and least predictive for MEHP. These results suggest that the most efficient exposure assessment strategy for a particular study may depend on the phthalates of interest. Key words: biomarkers, human, phthalates, reliability, urine. Environ Health Perspect 112:1734-1740 (2004) . doi:10.1289/ehp.7212 available via http://dx.doi.org/ [Online 16 August 2004]
Address correspondence to R. Hauser, Harvard School of Public Health, Department of Environmental Health, Occupational Health Program, Building 1, Room 1405, 665 Huntington Ave., Boston, MA 02115 USA. Telephone: (617) 432-3326. Fax: (617) 432-0219. E-mail: rhauser@hohp.harvard.edu We thank J. Reidy, A. Herbert, E. Samandar, and J. Preau from the Centers for Disease Control and Prevention and S. Duty, J. Frelich, L. Godfrey-Bailey, A. Trisini, and R. Dadd from the Harvard School of Public Health. This work was supported by grants ES09718 and ES00002 from the National Institute of Environmental Health Sciences (NIEHS) . Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NIEHS. The authors declare they have no competing financial interests. Received 27 April 2004 ; accepted 16 August 2004.
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