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Relatively few studies have been performed on the long-term effects of exposure to low levels of lead in childhood. Exposure to lead, a heavy metal, may result in serious central nervous system damage in infants and children. The toxic effects of lead exposure in childhood had been studied previously in a group of 270 young school children from 1975 to 1978. Although the subjects did not suffer from plumbism (lead poisoning) they did have abnormally high levels of lead that were detected in their teeth (dentin lead). The results of this earlier study revealed that these children had low IQ scores, poor classroom performance, and speech, language and attention problems. A follow-up study was performed with 132 individuals from this original group. These subjects, now young adults, were re-examined in 1988 to evaluate the long-term effects of their earlier lead exposure. In general, the findings from the subjects' earlier tests, which included cognitive impairment and retarded academic progress, persisted into adolescence. Young adults who had higher dentin lead levels as children were seven times more likely to drop out of high school and had lower class standings, weaker reading skills, greater absenteeism, and more impairment of motor skills such as hand-eye coordination. The authors pointed out that there was some level of selection bias in this study; individuals who were retested tended to be those with lower lead levels in childhood. Those with the highest lead concentrations, lowest socioeconomic status, and lowest IQs could not be located for follow-up. Therefore, the estimates made concerning the extent of damage from early lead exposure are conservative and actual effects may have been even more detrimental. (Consumer Summary produced by Reliance Medical Information, Inc.)