Relationship between urinary phthalate and bisphenol A concentrations and serum thyroid measures in U.S. adults and adolescents from the National Health and Nutrition Examination Survey (NHANES) 2007-2008

Environ Health Perspect. 2011 Oct;119(10):1396-402. doi: 10.1289/ehp.1103582. Epub 2011 Jul 11.


Background: Limited animal, in vitro, and human studies have reported that exposure to phthalates or bisphenol A (BPA) may affect thyroid signaling.

Objective: We explored the cross-sectional relationship between urinary concentrations of metabolites of di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), and BPA with a panel of serum thyroid measures among a representative sample of U.S. adults and adolescents.

Methods: We analyzed data on urinary biomarkers of exposure to phthalates and BPA, serum thyroid measures, and important covariates from 1,346 adults (ages ≥ 20 years) and 329 adolescents (ages 12-19 years) from the National Health and Nutrition Examination Survey (NHANES) 2007-2008 using multivariable linear regression.

Results: Among adults, we observed significant inverse relationships between urinary DEHP metabolites and total thyroxine (T4), free T4, total triiodothyronine (T3), and thyroglobulin, and positive relationships with thyroid-stimulating hormone (TSH). The strongest and most consistent relationships involved total T4, where adjusted regression coefficients for quintiles of oxidative DEHP metabolites displayed monotonic dose-dependent decreases in total T4 (p-value for trend < 0.0001). Suggestive inverse relationships between urinary BPA and total T4 and TSH were also observed. Conversely, among adolescents, we observed significant positive relationships between DEHP metabolites and total T3. Mono(3-carboxypropyl) phthalate, a secondary metabolite of both DBP and di-n-octyl phthalate, was associated with several thyroid measures in both age groups, whereas other DBP metabolites were not associated with thyroid measures.

Conclusions: These results support previous reports of associations between phthalates-and possibly BPA--and altered thyroid hormones. More detailed studies are needed to determine the temporal relationships and potential clinical and public health implications of these associations.

Publication types

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

MeSH terms

  • Adolescent
  • Benzhydryl Compounds
  • Child
  • Dibutyl Phthalate / urine
  • Diethylhexyl Phthalate / urine
  • Female
  • Humans
  • Male
  • Phenols / urine*
  • Phthalic Acids / urine*
  • Thyroid Hormones / blood*
  • Thyrotropin / blood
  • Thyroxine / blood
  • Triiodothyronine / blood
  • Young Adult


  • Benzhydryl Compounds
  • Phenols
  • Phthalic Acids
  • Thyroid Hormones
  • Triiodothyronine
  • Dibutyl Phthalate
  • phthalic acid
  • Thyrotropin
  • Diethylhexyl Phthalate
  • bisphenol A
  • Thyroxine