Exposure to phthalates in neonatal intensive care unit infants: urinary concentrations of monoesters and oxidative metabolites

Environ Health Perspect. 2006 Sep;114(9):1424-31. doi: 10.1289/ehp.8926.


Objective: We previously demonstrated that among 54 infants in neonatal intensive care units, exposure to polyvinyl chloride plastic medical devices containing the plasticizer di(2-ethylhexyl) phthalate (DEHP) is associated with urinary concentrations of mono(2-ethylhexyl) phthalate (MEHP) , a DEHP metabolite. In this follow-up report, we studied the neonates' exposure to DEHP-containing devices in relation to urinary concentrations of two other DEHP metabolites, and to urinary concentrations of metabolites of dibutyl phthalate (DBP) and benzylbutyl phthalate (BzBP) , phthalates found in construction materials and personal care products.

Measurements: A priori, we classified the intensiveness of these 54 infants' exposure to DEHP-containing medical products. We measured three metabolites of DEHP in infants' urine: MEHP and two of its oxidative metabolites, mono(2-ethyl-5-hydroxylhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) . We also measured monobutyl phthalate (MBP) , a metabolite of DBP, and monobenzyl phthalate (MBzP), a metabolite of BzBP.

Results: Intensiveness of DEHP-containing product use was monotonically associated with all three DEHP metabolites. Urinary concentrations of MEHHP and MEOHP among infants in the high-DEHP-intensiveness group were 13-14 times the concentrations among infants in the low-intensiveness group (p</= 0.007). Concentrations of MBP were somewhat higher in the medium- and high-DEHP-intensiveness group; MBzP did not vary by product use group. Incorporating all phthalate data into a structural equation model confirmed the specific monotonic association between intensiveness of product use and biologic measures of DEHP.

Conclusion: Inclusion of the oxidative metabolites MEHHP and MEOHP strengthened the association between intensiveness of product use and biologic indices of DEHP exposure over that observed with MEHP alone.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Biomarkers / urine
  • Child
  • Child, Preschool
  • Dibutyl Phthalate / toxicity
  • Dibutyl Phthalate / urine
  • Diethylhexyl Phthalate / analogs & derivatives
  • Diethylhexyl Phthalate / toxicity
  • Diethylhexyl Phthalate / urine
  • Environmental Exposure*
  • Environmental Monitoring*
  • Humans
  • Infant
  • Infant, Newborn
  • Intensive Care Units, Neonatal
  • Oxidation-Reduction
  • Phthalic Acids / toxicity*
  • Phthalic Acids / urine*
  • Plasticizers / toxicity*
  • Risk Factors
  • Sex Factors


  • Biomarkers
  • Phthalic Acids
  • Plasticizers
  • mono(2-ethyl-5-hydroxyhexyl) phthalate
  • Dibutyl Phthalate
  • mono(2-ethyl-5-oxohexyl)phthalate
  • Diethylhexyl Phthalate
  • mono-(2-ethylhexyl)phthalate
  • monobutyl phthalate