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Changes in children hair-Hg concentrations during the first 5 years: maternal, environmental and iatrogenic modifying

Rejane C Marques1, José G Dórea, Wanderley R Bastos

  • 1Fundação Universidade Federal de Rondônia, Porto Velho, RO, Brazil.

Regulatory Toxicology and Pharmacology : RTP
|June 15, 2007
PubMed

Insights

Infant mercury (Hg) levels peak at 6 months, differing from maternal levels, influenced by factors like thimerosal-containing vaccines (TCV) and infant development. Extended breastfeeding did not significantly alter these mercury concentrations.

Area of Science:

  • Environmental Health
  • Pediatric Toxicology
  • Neurodevelopmental Science

Background:

  • Children face mercury (Hg) exposure from maternal transfer, environmental sources, and thimerosal-containing vaccines (TCV).
  • Existing neurodevelopment studies using infant hair-Hg (HHg) often overlook infant physiological changes and specific Hg exposure factors.

Purpose of the Study:

  • To longitudinally analyze changes in infant and maternal hair-Hg (HHg) concentrations from birth to five years.
  • To investigate the factors contributing to the asymmetry in Hg exposure between mothers and children.

Main Methods:

  • A longitudinal study tracked HHg concentrations in children and mothers in Porto Velho, Brazilian Amazonia.
  • Data was collected at birth, 6 months (breastfeeding), 36 months (weaning), and 60 months (pre-school).
  • Statistical analysis, including Spearman's rank correlation, examined associations between maternal and infant HHg levels and other factors.

Main Results:

  • Infant HHg levels peaked at 6 months, distinct from maternal levels which were highest at childbirth.
  • Thimerosal-containing vaccines (TCV) and infant developmental stages, including transitional diets, likely contribute to the observed HHg asymmetry.
  • Extended lactation (up to 36 months) showed no significant association with infant or maternal HHg levels.
  • Significant correlations between maternal and infant HHg were observed at birth, 6 months, 3 years, and 5 years.

Conclusions:

  • Infant mercury exposure dynamics differ significantly from maternal exposure, influenced by developmental transitions and potential vaccine contributions.
  • Maternal postpartum changes, infant development, dietary shifts, and possibly TCV are key factors in the observed mercury level disparities.
  • Understanding these factors is crucial for accurate neurodevelopmental risk assessment in children.

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