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| Author(s): |
Glauce Regina Costa de Almeida
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba |
| Defense date: | 2009-02-20 |
| Examining board members: |
Raquel Fernanda Gerlach;
Antonio Luiz Rodrigues Júnior;
Sergio Roberto Peres Line;
Eduardo Mello De Capitani;
Christie Ramos Andrade Leite Panissi
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| Advisor: | Raquel Fernanda Gerlach |
| Abstract | |
With increasing evidence of adverse health effects of lower levels of lead (below 10 $g/dL in whole blood), studies on novel internal dose biomarkers are needed. In Brazil, some studies showed high amounts of lead in the superficial enamel of deciduous enamel. The aim of this study was 1) to determine and to correlate the lead concentration in children living in Campos Elíseos district (in Ribeirao Preto, SP, Brazil), in whole blood (BL), serum, saliva, and surface enamel; 2) to correlate lead concentrations found using these biomarkers with anemia; 3) to evaluate the influence of ALAD and VDR polymorphisms on lead concentrations in these biomarkers. 444 children aged 6-8 years were enrolled in this study. BL, serum, parotid, submandibular and whole saliva were collected in trace element free tubes. Two successive acid etch enamel microbiopsies were performed on one deciduous and one permanent teeth. Phosphorus was colorimetrically determined to calculated microbiopsy depth. Lead concentrations were determined by inductively coupled plasma mass spectrometry (ICPMS). The detection limit (DL) was 0.03 $g/L (serum) and 0.02 $g/L (saliva). The hemoglobin level was determined by an automated cell counter (Micros - ABX). Genotypes for the ALAD and VDR polymorphism were determined by PCR and restriction fragment length digestion. For correlations, children were subdivided in two groups according to BL concentration (< 4 and = 4 $g/dL) and enamel lead concentration (< 400 and = 400 $g/g). Statistical significance was accepted when p< 0.05. BL and serum lead levels ranged from 0.2 to 9.4 (median, 2.1) $g/dL and < DL to 2.6 (median, 0.4) $g/L, respectively. 10% of the children showed BL above 4 $g/dL. Boys showed higher BL concentrations than girls (2.3 versus 2.0 $g/dL, p< 0.0003). Lead concentrations in whole, sublingual and parotid saliva were 1.7, 1.4 and 1.3 $g/L, respectively. No correlations between BL and serum, and between BL and saliva lead concentrations were found, nor between serum lead versus whole, sub and parotid lead values. The median lead concentrations found in the first and second deciduous tooth enamel microbiopsy were 109.3 and 45.9 $g/g, respectively, when median biopsy depths were 3.1 and 7.0 $m. For the first and second microbiopsies in permanent teeth, median lead concentrations were 308.3 and 99.7 $g/g, respectively, and median biopsy depths were 2.9 and 6.0 $m, respectively. There was no correlation between BL and enamel lead. Nine % (n= 35) and 3% (n= 12) of the children showed surface enamel lead levels in the first and second deciduous enamel microbiopsy = 400 $g/g, respectively, and 33% (n= 92) and 7% (n= 18) had lead = 400 $g/g in the first and second permanent enamel microbiopsies, respectively. A significant correlation between serum and enamel lead levels was found for children with surface enamel lead concentrations = 400 $g/g (r= 0.65, p< 0.0001 for deciduous and 0.51, p< 0.0001 for permanent teeth). No correlation was found between lead content in enamel and saliva. No difference between the distribution of ALAD alleles and among VDR alleles (for BsmI, ApaI and FokI polymorphisms) and BL, serum and enamel lead levels was found. In conclusion, our data showed an undue exposure in the study population of 6-8-yearsold children living in Campos Elíseos (Ribeirão Preto, SP), as observed in the BL and enamel samples. We found a strong correlation between serum and enamel lead levels only for children who were probably more exposed to lead. Our data suggests that sources of exposure to lead by children deserve further studies in Brazil, as well as the BL lead levels of younger children. (AU) | |