Children more vulnerable to harmful effects of lead

May 04, 2008

Contrary to prevailing assumptions, children are more vulnerable to the harmful effects of lead exposure at the age of 6 than they are in early childhood, according to a Cincinnati Children’s Hospital Medical Center study to be presented May 4 at the annual meeting of the Pediatric Academic Societies in Honolulu.

“Although we typically worry about protecting toddlers from lead exposure, our study shows that parents and pediatricians should be just as, if not more concerned about lead exposure in school-aged children,” says Richard Hornung, Dr.P.H., a researcher in the division of general and community pediatrics at Cincinnati Children’s and the study’s main author.

The researchers found that blood lead concentrations (BPb) at age 6, compared to those at younger ages, are more strongly associated with IQ and reduced volume of gray matter in the prefrontal cortex of the brain, which is involved in planning, complex thinking and moderating behavior.

Overall, the children’s average BPb levels peaked at 13.9 micrograms of lead per deciliter of blood at age 2, then declined to an average of 7.3 micrograms per deciliter by age 6. For children, however, with the same average blood lead levels through age 6, those who received more of their exposure at age 6 had substantially greater decrements in intellectual ability than those more heavily exposed at age 2.

“Lead toxicity is difficult to recognize in a clinical setting, but it can have devastating effects,” says Bruce Lanphear, M.D., director of the Cincinnati Children’s Environmental Health Center and the study’s senior author. “We found that children may be particularly vulnerable to lead exposure just as the child approaches school age, during a period of rapid cognitive development.

Because IQ tests were not administered to children older than 6, it is unknown whether older children are even more vulnerable to environmental lead exposure, according to Dr. Hornung.

Approximately 310,000 U.S. children age 1 to 5 years have blood lead levels greater than 10 micrograms per deciliter, the level at which the Centers for Disease Control and Prevention recommends public health actions be initiated. But research has consistently shown that blood lead levels considerably lower than 10 micrograms per deciliter are associated with adverse effects.

Federal and state regulatory standards have helped to minimize or eliminate the amount of lead in U.S. consumer products and occupational settings, according to the National Institute of Environmental Health Sciences (NIEHS). Today, the most common sources of lead exposure in the United States are lead-based paint in older homes, contaminated soil, household dust, drinking water, lead crystal and lead-glazed pottery.

While extreme lead exposure can cause a variety of neurological disorders, such as lack of muscular coordination, convulsions and coma, lower lead levels have been associated with measurable deficits in children’s mental development and behavioral problems. These include hyperactivity, or ADHD, lowered performance on intelligence tests, and deficits in fine motor function, hand-eye coordination and reaction time. Chronic lead exposure in adults can result in increased blood pressure, decreased fertility, cataracts, nerve disorders, muscle and joint pain as well as problems with memory or concentration.

Source: Cincinnati Children's Hospital Medical Center

Explore further: ER waiting times vary significantly, studies find

add to favorites email to friend print save as pdf

Related Stories

Tropical fish a threat to Mediterranean Sea ecosystems

1 hour ago

The tropical rabbitfish which have devastated algal forests in the eastern Mediterranean Sea pose a major threat to the entire Mediterranean basin if their distribution continues to expand as the climate ...

The latest observations of interstellar particles

1 hour ago

With all the news about Voyager 1 leaving the heliosphere and entering interstellar space you might think that the probe is the first spacecraft to detect interstellar particles. That isn't entirely true, ...

Indie game developers sprouting at Tokyo Game Show

1 hour ago

Nestled among the industry giants at the Tokyo Game Show Thursday are a growing number of small and independent games developers from Asia and Europe, all hoping they are sitting on the next Minecraft.

Recommended for you

ER waiting times vary significantly, studies find

2 hours ago

(HealthDay)—When it comes to emergency room waiting times, patients seeking care at larger urban hospitals are likely to spend more time staring down the clock than those seen at smaller or more rural facilities, ...

Internists report considerable EMR-linked time loss

2 hours ago

(HealthDay)—Use of electronic medical record (EMR) systems is associated with considerable loss of free time per clinic day, according to a research letter published online Sept. 8 in JAMA Internal Medicine.

Kids eat better if their parents went to college

3 hours ago

Children of college-educated parents eat more vegetables and drink less sugar, according to a new study from the University of British Columbia. But it's still not enough, the study goes on to say, as all kids are falling ...

User comments : 0