Biomonitoraggio umano: effetti sub-clinici da Piombo e Cadmio sull’accrescimento

Objectives: The aims of this study are: 1) to assess the exposure to Pb and Cd in Sardinian children by hair analysis; 2) to detect any possible sub-clinical impact on growth due to exposure to these heavy metals; 3) to evaluate the individual susceptibility to absorption by using genetic polymorphisms involved in Pb and Cd metabolisms,. Methods: The total sample consists of 144 children of both sexes (11-14 years), living in different municipalities of Sardinia (Italy) of Sulcis-Iglesiente area, Sant’Antioco and Iglesias, collected from January and March 2013. The Anthropometric variables considered are height, sitting height, estimated lower limb length (height minus sitting height) and cephalic circumference. The environmental variables are hair lead and cadmium concentrations (PbH, CdH), proxy of socioeconomic status (SES), proxy of nutritional status as upper arm muscle area (UMA), upper arm fat area (UFA), body mass index (BMI) and Σ 5 skinfolds. In order to detect possible associations between genetic factors and heavy metal concentration, the following genetic polymorphisms were studied: δ- aminolevulinic acid dehydratase (ALAD), vitamin D receptor (VDR), DNAmethyltransferase 1 gene (DNMT1) and DNA-methyltransferase 3 gene (DNMT3). Hair Lead (PbH) and cadmium (CdH) concentrations were assessed by inductively coupled plasma atomic mass spectrometry (ICP-MS) Statistical analyses : For each sample, it has been calculated the descriptive statistics for anthropometric and sociodemographic variables, and the hair lead and cadmium level. One-way analysis of variance (ANOVA) was used to test for significant differences between the samples for all the considered variables. To evaluate the sub-clinical impact on growth, we carried out a multivariate ridge regression analysis with the anthropometric measures (height, sitting height, estimated lower limb length) as dependent variables and demographic variables, proxy of socioeconomic, proxy of nutritional status, levels of PBH and CDH, polymorphisms genetic as independent variable. Results: Statistically significant differences (p<0,01) in elemental concentration levels between the two study sites were found. Hair of children from Iglesias exhibited much higher concentration values for Cd and Pb compared to Sant'Antioco children. Multivariate ridge regression analyses indicates a sub-clinical impact of cadmium and lead on growth, but failed to reveal any association between lead and cadmium levels and genetic polymorphisms. Conclusions: The results support the use of hair lead and cadmium levels as a biomarker to assess either differences between samples from different environmental background or the impact of subclinical lead on the physical growth of children. No significant association between alleles at genetic polymorphisms taken into consideration and lead and cadmium concentrations levels was observed. However, further studies using larger population samples and genetic polymorphisms covering a wider range of enzymatic and metabolic aspects are needed for definite conclusions to be drawn.