Increased Lead Burdens and Trace Mineral Status of Mentally Retarded Children

Recent research has suggested that children with a moderate increase in body burden of lead, although clinically asymptomatic, may be subject to impaired mental development. This study investigated the relationship between low-level lead absorption and mild and border-line mental retardation, and evaluated the rela-tionships among nutrient minerals, heavy metals, and increased lead burdens. Hair trace-mineral concentrations were compared in a group of retarded children with a non-retarded control group. The retarded group had significantly raised hair-lead concentra-tions. There were also differences in the mean levels of six nutrient minerals. Further, there were indications that lead and other toxic metals occur together in the retarded. It is concluded that continuing research is needed to study the relationship between retardation and lead burdens. Children who survive lead poisoning are at risk for severe mental retardation resulting from damage to the central nervous system (Byers & Lord, 1943). More recent research has suggested that children with a moderate increase in body burden of lead, although clinically asymptomatic, may also be subject to impaired mental development, albeit a more difficult type to define. Low ele-vated lead levels previously thought harmless are now being associated with mild mental retardation and impaired IQ (David, McGann, Hoffman, & Sverd