Lead and cognitive function in VDR genotypes in the third National Health and Nutrition Examination Survey.

The relationship between the blood lead concentration and cognitive function in children and adults with different VDR genotypes who participated in the third National Health and Nutrition Examination Survey was investigated. The relationship between blood lead and serum homocysteine concentrations was also investigated. In children 12 to 16 years old, performance on the digit span and arithmetic tests as a function of the blood lead concentration varied by VDR rs2239185 and VDR rs731236 genotypes. Decreases in performance occurred in some genotypes, but not in others. In adults 20 to 59 years old, performance on the symbol-digit substitution test as a function of the blood lead concentration varied by VDR rs2239185-rs731236 haplotype. In the 12 to 16 year old children and adults 60 or more years old, the relationship between the serum homocysteine and blood lead concentrations varied by VDR genotype. The mean blood lead concentrations of the children and adults did not vary by VDR genotype.