Within-person variability in urinary bisphenol A concentrations: measurements from specimens after long-term frozen storage.

Author(s): Nepomnaschy PA, Baird DD, Weinberg CR, Hoppin JA, Longnecker MP, Wilcox AJ

Publication: Environ Res, 2009, Vol. 109, Page 734-7

PubMed ID: 19463991 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of long-term frozen storage (22-24 y), daily variability, and stage in menstrual cycle on BPA concentrations in urine specimens from women. First morning urine specimens underwent at least 2 freeze-thaw cycles prior to the present study. The specimens subjected to long-term frozen storage did not undergo similar analysis prior to long-term storage, but the authors compared their results to another study which measured phthalate metabolites in more recently collected specimens (3-11 years later).

   Summary of Findings:

   BPA levels showed an insignificant increase over the 3 year collection period (1983-1985) consistent with the rise in US BPA production between 1980 and 1985. Significant variability in BPA measurements both between women and between specimens taken from the same woman was observed, but intra-individual variation was larger than inter-woman variability. BPA levels were not significantly influence by or associated with phase of menstrual cycle at the time of collection. The interquartile range of BPA levels was slightly higher in this study (specimens collected in 1983-1985) than reported for NHANES urine specimens collected in 1988-1994. The authors conclude that BPA is relatively stable after long-term frozen storage.

   Biospecimens

   • Bodily Fluid - Urine

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Small molecule	LC-MS or LC-MS/MS
   Protein	Colorimetric assay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Acquisition	Time of biospecimen collection	During follicular phase of menstrual cycle During luteal phase of menstrual cycle
   Storage	Storage duration	22 y (from 1985) 23 y (from 1984) 24 y (from 1983)

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