Low blood lead concentrations and thyroid function of American adults

Int J Environ Health Res. 2013 Dec;23(6):461-73. doi: 10.1080/09603123.2012.755155. Epub 2013 Jan 16.


Lead is often present in our environment, but its effect on thyroid function is still unclear. In this study, multiple linear regressions were performed between log-transformed blood lead levels and thyroid function parameters of 4652 adults from the 2007-2008 National Health and Nutrition Examination Survey. The models were adjusted for age, gender, race/ethnicity, smoking, alcohol consumption, body mass index, physical activity, iodine intake, medications, and bone mineral density. Blood lead concentrations (mean: 1.52 ± 1.20 μg/dL [range 0.18-33.12]) were inversely associated with total thyroxine (regression coefficients [β]: -0.22 [95% CI: -0.34, -0.09] in the general population, but were not correlated with thyroid stimulating hormone, total or free triiodothyronine, nor free thyroxine. Blood lead may have no effect on the thyroid function; however, it could be associated with decreased concentrations in thyroid-binding proteins.

MeSH terms

  • Adult
  • Aged
  • Cross-Sectional Studies
  • Environmental Exposure*
  • Environmental Monitoring
  • Female
  • Humans
  • Immunoassay
  • Lead / blood*
  • Linear Models
  • Male
  • Mass Spectrometry
  • Middle Aged
  • Nutrition Surveys
  • Thyrotropin / blood*
  • Thyroxine / blood*
  • Triiodothyronine / blood*
  • United States
  • Young Adult


  • Triiodothyronine
  • Lead
  • Thyrotropin
  • Thyroxine