Comparison of patella lead with blood lead and tibia lead and their associations with neurobehavioral test scores.

OBJECTIVE: Lead exposure in adults is associated with worse cognitive function in cross-sectional and longitudinal studies. Previous studies have mainly examined relations with blood lead or cortical bone lead; few have examined trabecular bone lead. METHODS: We performed a cross-sectional analysis of the relations of patella lead and other lead biomarkers with measures of neurobehavioral and peripheral nervous system function in 652 lead workers. RESULTS: Patella lead was found to be associated with worse performance on seven of 19 tests of manual dexterity, sensory vibration threshold, and depressive symptoms. The associations of patella lead with cognitive function were essentially similar to those with blood lead or tibia lead but of somewhat lower magnitude. CONCLUSIONS: In this study, measurement of patella lead did not aid causal inference regarding cognitive effects when compared with blood lead and tibia lead.

The protective effect of delta-aminolevulinic acid dehydratase 1-2 and 2-2 isozymes against blood lead with higher hematologic parameters.

Previous studies have suggested that delta-aminolevulinic acid dehydratase (ALAD) types 1-2 or 2-2 are protective against the toxicity of blood lead (PbB) when zinc protoporphyrin (ZPP) levels are low because of differential binding of lead in erythrocytes. The hypothesis is that subjects with the ALAD 1-1 genotype are more susceptible to lead exposure with impaired hematologic synthesis and therefore that iron nutrition is more important in those with the ALAD 1-1 genotype. The purpose of this study was to prove the protective effect of ALAD 1-2/2-2 against PbB with higher hematologic parameters. Data on 1,219 male workers from eight lead-using factories in the Republic of Korea were examined in this cross-sectional study. Blood samples were evaluated for PbB, ZPP, hemoglobin (Hb), and serum iron (SFe) concentrations and ALAD genotypes. The overall prevalence of the ALAD 1-2/2-2 genotype was 9.3%, which was associated with lower log ZPP (p < 0.001) and higher Hb (p = 0.014) levels. For the subjects with normal iron status (SFe levels > 60 micro g/dL), those with the ALAD 1-1 genotype were more likely to be anemic (adjusted odds ratio of 5.2; 95% confidence interval, 1.2-22.6) than those with ALAD 1-2/2-2. The study confirms the protective effects of ALAD 1-2/2-2 polymorphisms against PbB on hematologic pathways. In order to promote health and to minimize the toxicity of lead exposure more effectively, the nutritional management of iron in Korean workers should take both their ALAD genotypes and occupational lead exposures into account.