Blood Lead and Information Processing Slowing in Working Age Adults

Stephen. W. Harkins

Advisor, R. Leonard Vance

Objective: The purpose of this paper was to explore the relation between lead and mental processing efficiency in adults. Lead is a central nervous system poison that impairs mental and behavioral development. Healthy People 2010 established a target blood lead level (BLL) for children of 0 μg/dL by 2010, but is silent with regard to recommended changes for BLLs standards in working age adults.

Methods: The relation of BLL to performance on two neurobehavioral tests was assessed in working age adults (N = 4909; Age 20 to 59 years; 51.4% Female) employing data from the Third National Health and Nutrition Survey (NHANES III).

Results: Multiple linear regression analyses indicated a significant effect of BLL on time taken to complete an attention demanding cognitive task (Symbol Digit Substitution Task, SDST) but not accuracy or simple reaction time, after controlling for confounding variables of age, sex, race-ethnicity, and education. Persons with BLL ≥ 5 μg /dL took longer (multivariate adjusted mean = 23.6 Sec, SE = 0.30) compared to individuals with BLLs < 5 μg /dL (mean = 22.5 Sec, SE = 0.14).

Conclusions: The results suggest that lead burden in working age persons impairs central nervous processes involving executive mental functions (decision speed and attention).