Low Levels of Lead Poisoning Can Lower Early Reading Skills: Study

New research suggests that even low levels of lead in the blood can affect a child’s school performance, specifically reading readiness for children entering kindergarten. The findings provide support for recent reductions in the threshold for a lead poisoning diagnosis.

A study published in the medical journal Pediatrics this week focuses on 3,400 children attending public kindergarten in Providence, Rhode Island. Researchers linked the children’s reading readiness test scores to information regarding blood lead levels taken from state health department records.

Researchers found children with blood lead levels between 5 and 9 mcg/dl were 21% more likely to score below the national benchmark on the reading readiness test. Their test scores were also 4.5 points lower than children who had blood lead levels under 0.5 mcg/dl.

Children who had blood lead levels of 10 mcg/dl or greater were 56% more likely to score below the national bench mark. These children’s scores were also 10 points lower than their peers. Reading-readiness tests at the kindergarten level are strong indicators of a child’s school performance later in life. The study found even children with blood lead levels as low as 2 mcg/dl were affected.

This new study reveals even low blood lead levels may still affect children and cause harmful adverse affects. The children with what officials deem low levels of lead in the blood still scored lower on the reading readiness test.

No “Safe” Lead Exposure Level

Until last year the blood lead level threshold for lead poisoning was marked at 10 mcg/dl. In May 2012 the CDC lowered the exposure level to 5 mcg/dl.

The blood lead level threshold reduction dramatically increased the number of children considered to be suffering from lead poisoning.

Researchers in this latest study emphasize that there is no safe level of lead exposure and additional research should be conducted on other high risk U.S. populations to obtain an accurate picture of how lead exposure affects children. They also highlight many children remain at risk and officials must act to identify and help them.

Lead exposure has been linked to developmental problems in children and may even lower IQ. Other side effects of lead poisoning can include injury to the nervous system, seizures, growth or mental retardation, coma and death.

One of the most common causes of lead poisoning in the United States is lead based paint, which was banned in this country in 1978 due to the risk of severe and permanent brain damage it posed, especially among children.

Lead paint is still found in many old homes and in public housing in many urban areas. Approximately 4 million homes around the country expose children to lead through old, chipped, lead based paint. Approximately half a million children have blood lead levels between 1 and 5 mcg/dl, according to the CDC.