Lead poisoning: from screening to primary prevention.

Knowledge of the extent and seriousness of childhood lead poisoning has vastly expanded since the last statement regarding lead poisoning by the American Academy of Pediatrics in 1987.’ Blood lead 1evels once thought to be safe have been shown to be associated with IQ deficits, behavior disorders, slowed growth, and impaired hearing.2 In fact, lead poisoning is, according to the Department of Health and Human Services, “the most important environmental health problem for young children.”3 The rapid development of the scientific database requires recognition by physicians of the significance of effects at lower levels and a change in clinical practice. During the last 30 years the Centers for Disease Control and Prevention (CDC) has revised downward the definition of the blood level at which lead poisoning occurs from 60 pg/dL whole blood in the early 1960s, to 30 pg/dL in 1975, and 25 jig/dL in 1985. The 1991 CDC statement “Preventing Lead Poisoning in Young Children” recommended lowering the community intervention level to 10 pg/dL and setting several action levels (Table 1).2 In 1987 the American Academy of Pediatrics stated that lead 1evels greater than 25 pg/dL were unacceptable for children.1 The Academy now recognizes that impairment of cognitive function begins to occur at levels greater than 10 pg/dL, even though clinical symptoms are not seen. In the late 1970s, the average blood lead level for US children was 16 pg/dL.4 The mean blood lead level for US children has declined since 1976 due to the phaseout of lead in gasoline5 and the reduction of lead in food, and it is now between 4 and 6 pg/dL.6 However, severe lead poisoning still occurs, and there are stifi many children at high risk of exposure. Childhood lead poisoning is preventable. In January 1991, the US Public Health Service issued a strategic plan to eradicate childhood lead poisoning which included a cost-benefit analysis.7 This represents a major change from primarily finding and treating exposed children toward an emphasis on preventing lead exposure. Identification and treatment of the child poisoned with lead continues to be essential, but of greater importance is identification of the source and prevention of subsequent exposures for that child and other children in the future. Until children are in lead-free environments, blood lead screening is essential to prevent serious disease