Getting the Lead Out (of Our Kids)

Lead exposure to children continues to decrease but disparities remain

(RxWiki News) We've come a long way since the days when gasoline and paint contained lead. Too much lead exposure can cause lasting neurological problems. The good news is that lead exposure levels continue to drop.

The Centers for Disease Control and Prevention have released a report about the most recent estimates for blood lead levels in preschool children. This report reveals that the decrease in lead exposure started several decades ago has continued. 

However, some children remain at risk for exposures. 

Researchers have found having too much lead in a child's blood can cause learning and behavior problems.

"Ask your doctor how to further avoid lead exposure."

The report, authored by William Wheeler, MPH, of the Division of Nutrition, Physical Activity and Obesity at the CDC, aimed to understand how many children aged 1 to 5 are at risk for dangerous levels of lead exposure.

The researchers pulled data from two sets of the National Health and Nutrition Examination Survey, one from 1999-2002 and one from 2007-2010. These surveys are conducted on a regular basis in the US and involve gathering data from approximately 1,240 children.

The analysis from the 2007-2010 survey revealed approximately 2.6 percent of preschool children had blood lead levels at or higher than 5μg/dL. Using the 2010 Census numbers, this translates to approximately 535,000 children in the US.

Previously, the CDC had defined blood lead levels of 10μg/dL or higher as the "level of concern" for children in 1991.

However, the authors of this report have determined  5μg/dL is defined as "high" in this report based on additional data from children's blood samples in these surveys since 1991.

One reason for redefining the blood lead levels that the CDC finds concerning is that no safe maximum level for lead in children's blood has been determined. Researchers are unsure at what blood lead level the negative effects of lead might occur.

The number of children at risk for high blood lead levels has decreased considerably in the past several decades. In the 1976-1980 survey, approximately 88 percent of children between the ages of 1 and 5 had blood lead levels over 10 μg/dL.

That percentage dropped to 4.4 percent in the 1991-1994 survey, then 1.6 percent in the 1999-2002 survey, then 0.8 percent in the 2007-2010 survey.

"Substantial progress has been made over the past four decades in reducing the number of children with elevated blood lead levels," the authors wrote. The reductions have occurred because of a variety of policies reducing environmental lead exposure, the authors wrote.

These policies include removing lead from gasoline and house paint, reducing lead concentrations in the air and water, removing lead from children's toys and products and screening high-risk populations for lead exposure.

"The greatest reductions have occurred among children in racial/ethnic and income groups that historically were most likely to have blood lead levels equal to or greater than 10 μg/dL," the authors noted. However, inequalities in risk of blood lead levels still exist among different groups.

The researchers in this report also looked at how the blood lead levels among children in this age group break down in terms of the children's demographics. In general, a higher percentage of minority and low-income children are at risk for high blood lead levels.

Based on the 2007-2010 survey data, an estimated 3.3 to 8.4 percent of black children are at risk for blood lead levels over 5 μg/dL, compared to 0.7 to 5.2 percent of white children.

The average middle level measurement of blood lead levels among lower income children was also slightly higher than that of children from middle income and higher income groups.

The report was published April 4 in the CDC's Morbidity and Mortality Weekly Report.

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Review Date: 
April 4, 2013