CDC Updates Guidelines for Children’s Lead Exposure

In response to the growing body of scientific evidence about effects of exposure to low levels of lead, 1 the U.S. Centers for Disease Control and Prevention (CDC) has announced it is changing its guidelines for children's exposure to the toxic metal, reducing by half the blood lead level at which intervention is recommended. 2 According to CDC spokesman Jay Dempsey, the agency estimates the change will increase the number of affected children from fewer than 100,000 to 372,979. Recommended intervention involves identifying and removing sources of lead exposure and follow-up blood lead monitoring. Since 1991 the CDC's " level of concern " for lead in children's blood had been set at 10 µg/dL. At the recommendation of its Advisory Committee on Childhood Lead Poisoning Prevention, the agency is dispensing with the use of a static number. Instead, its new reference value of 5 µg/dL is based on the 97.5th percentile of blood lead levels in U.S. children aged 1–5 years, as measured by the agency's National Health and Nutrition Examination Survey (NHANES). The reference value will be updated every four years based on the two most recent iterations of the NHANES. 2 The CDC has moved away from the " level of concern " terminology because it " gives a false sense of security to people " whose children's blood lead fell below the cutoff, says Christopher Portier, director of the agency's National Center for Environmental Health. The agency and its advisory committee can find no evidence that there is a safe level of lead exposure for children, he says. A host of studies now link exposure to lower levels of lead with behavior problems, attention deficit/hyperactivity disorder, and adverse cardiovascular, immunological, and endocrine effects, says Bruce Lanphear of Simon Fraser University. Lanphear led a 2005 study in which seven different longitudinal cohorts from multiple countries reported very similar decreases in intelligence in association with blood lead levels below 10 µg/dL. 3 In June 2012 the National Toxicology Program concluded that adverse health effects occur at levels below even 5 µg/dL. 4 Homes can be a major source of lead exposure, and the CDC is focused on primary prevention, says Mary Jean Brown, chief of the agency's Lead Poisoning Prevention Branch. " We have to develop an agenda that controls or eliminates lead hazards before children are poisoned, " she says. The CDC is working with the U.S. Department …