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Lead in saliva from lead-exposed and unexposed children
Glauce Regina Costa de Almeida1, Clarice Umbelino de Freitas, Fernando Barbosa
1Department of Morphology, Stomatology and Physiology, Dental School of Ribeirão Preto, University of São Paulo-FORP/USP, Av. do Café, S/N, Monte Alegre, CEP 14040-904, Ribeirão Preto-SP, Brazil. glauce79@yahoo.com.br
Insights
Saliva lead levels (Pb-saliva) were significantly higher in children from a lead-contaminated region compared to a non-contaminated area. While Pb-saliva showed a relationship with environmental lead, its correlation with lead in tooth enamel requires further investigation for use as a biomarker.
Area of Science:
- Environmental Health
- Biomonitoring
- Pediatric Toxicology
Background:
- Whole blood is the standard for diagnosing lead exposure.
- A non-invasive biomonitoring method for lead contamination is needed.
- This study investigates saliva lead content (Pb-saliva) in children from contaminated and non-contaminated regions.
Purpose of the Study:
- Compare Pb-saliva in children from Ribeirão Preto (no contamination) and Bauru (lead contamination).
- Correlate Pb-saliva with lead content in children's tooth enamel (Pb-enamel).
Main Methods:
- Analyzed Pb-saliva in 125 children from Ribeirão Preto and 19 from Bauru using ICP-MS.
- Utilized existing Pb-enamel data from a previous study for correlation.
- Employed Mann-Whitney test for inter-city comparison and Pearson's correlation for Pb-saliva and Pb-enamel.
Main Results:
- Median Pb-saliva was significantly higher in Bauru (5.85 microg/L) than Ribeirão Preto (1.64 microg/L) (p<0.0001).
- Pearson's correlation coefficients for Log10 Pb-saliva vs. Log10 Pb-enamel were 0.15 (p=0.08) for Ribeirão Preto and 0.38 (p=0.11) for Bauru.
Conclusions:
- Saliva lead levels reflect environmental lead contamination.
- Further research is needed to establish saliva's utility as a biomarker for lead exposure in children.
Introduction:
Whole blood is used for diagnosis of lead exposure. A non-invasive method to obtain samples for the biomonitoring of lead contamination has become a necessity. This study 1) compares the lead content in whole saliva samples (Pb-saliva) of children from a city with no reported lead contamination (Ribeirão Preto, São Paulo State, Brazil) and children of a region notoriously contaminated with lead (Bauru, São Paulo State, Brazil), and 2) correlates Pb-saliva with the lead content in the enamel microbiopsy samples (Pb-enamel) in the case of these two populations.
Methods:
From a population of our previous study that had included 247 children (4- to 6-year-old) from Ribeirão Preto, and 26 children from Bauru, Pb-saliva was analyzed in 125 children from Ribeirão Preto and 19 children from Bauru by inductively coupled plasma mass spectrometry (ICPMS). To correlate Pb-saliva with Pb-enamel, we used Pb-enamel data obtained in our previous study. The Mann-Whitney test was employed to compare the Pb-saliva data of the two cities. Pb-saliva and Pb-enamel values were then Log10 transformed to normalize data, and Pb-saliva and Pb-enamel were correlated using Pearson's correlation coefficient.
Results:
Median Pb-saliva from the Ribeirão Preto population (1.64 microg/L) and the Bauru population (5.85 microg/L) were statistically different (p<0.0001). Pearson's correlation coefficient for Log10 Pb-saliva versus Log10 Pb-enamel was 0.15 (p=0.08) for Ribeirão Preto and 0.38 (p=0.11) for Bauru.
Conclusions:
A clear relationship between Pb-saliva and environmental contamination by lead is shown. Further studies on Pb-saliva should be undertaken to elucidate the usefulness of saliva as a biomarker of lead exposure, particularly in children.
