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Dose-response curves for erythrocyte protoporphyrin vs blood lead: effects of iron status

A H Marcus1, J Schwartz

  • 1U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711.

Environmental Research
|December 1, 1987
PubMed

Insights

Erythrocyte protoporphyrin (EP) levels increase with lead exposure in children. Lower iron status, indicated by percentage transferrin saturation (PTS), exacerbates this adverse biological response to lead.

Area of Science:

  • Environmental Health
  • Toxicology
  • Pediatrics

Background:

  • Elevated erythrocyte protoporphyrin (EP) is a key biomarker for lead exposure's adverse biological effects.
  • Lead exposure in children is a significant public health concern, impacting development and well-being.
  • Iron status plays a crucial role in the body's response to environmental toxins.

Purpose of the Study:

  • To model the relationship between blood lead concentration (PbB) and EP in U.S. children.
  • To investigate the influence of iron status, specifically percentage transferrin saturation (PTS), on this dose-response relationship.
  • To understand how red cell lead-holding capacity is affected by iron status.

Main Methods:

  • Utilized data from 1677 U.S. children (ages 2-6 years) from the Second National Health and Nutrition Examination Survey (NHANES II).
  • Developed and fitted a nonlinear mathematical model to describe the EP vs. PbB relationship.
  • Defined iron status using percentage transferrin saturation (PTS) and analyzed its impact on model parameters.

Main Results:

  • A significant dose-response relationship was observed between EP and PbB.
  • The EP vs. PbB curves shifted upward with decreasing PTS, indicating a heightened response at lower iron status.
  • A key model parameter, proportional to red cell lead-holding capacity, decreased with lower PTS, explaining the exacerbated EP elevation.

Conclusions:

  • Iron status significantly modifies the biological response to lead exposure in children.
  • Children with poorer iron status exhibit a more pronounced increase in EP for a given blood lead concentration.
  • This highlights the importance of assessing and addressing iron status in children with lead exposure.

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