Even Low Lead Exposure Increases Risk of Behavioral Problems in Kids

Even low levels of blood lead levels elevate the risk of behavioral problems in children, a new study reveals.

Lead is known to be toxic and is particularly dangerous for unborn babies and young children as it damages the brain and nervous system. Even small amounts of lead can trigger serious health issues as lead is a neurotoxin. A new study found that even minute levels of lead in a child's blood trigger emotional and behavioral problems including depression, aggressiveness and anxiousness.

"This research focused on lower blood lead levels than most other studies and adds more evidence that there is no safe lead level," explained NIEHS administrator Kimberly Gray, Ph.D. "It is important to continue to study lead exposure in children around the world, and to fully understand short-term and long-term behavioral changes across developmental milestones. It is well-documented that lead exposure lowers the IQ of children."

In this study, the researchers measured the blood lead concentrations in more than 1,300 preschool children in China aged 3-5. They assessed the behavioral problems at the age of 6 using a standard questionnaire. The children's teachers and parents answered queries based on which their strengths and limitations were marked. The scores were used from two sources but the ratings do not give a clinical diagnostic measure of behavioral problems.

The researchers noticed that the blood lead concentrations were linked with elevated risk of behavioral as well as emotional problems.  The average blood lead level in children was 6.4 micrograms per deciliter.

"Young children are particularly vulnerable to the toxic effects of lead, because lead can affect children's developing nerves and brains," said senior author Jianghong Liu, Ph.D., from the University of Pennsylvania School of Nursing, Philadelphia.

Lead is a naturally occurring toxic metal and exposure occurs due to human activities including fossil fuels, mining and manufacturing.  In the U.S., main sources of lead exposure are lead-containing products such as paint, caulking and pipe solder.

"The sources of lead exposure may explain why concentrations of lead are different," explained Liu. "In China, we found that blood lead concentrations increased with age in preschool children. In the United States, however, blood lead concentrations increase with age in children up to 2-3 years old and then decline."

The finding was documented in journal JAMA Pediatrics.