Featured Research

from universities, journals, and other organizations

Drug Treatment Of Lead-Exposed Children Does Not Improve Psychological Test Scores

Date:
May 10, 2001
Source:
NIH/National Institute Of Environmental Health Sciences
Summary:
Using a lead-lowering drug to reverse the IQ damage associated with the lead exposure has proved ineffective, the National Institute of Environmental Health Sciences announced.

May 9, 2001 -- Using a lead-lowering drug to reverse the IQ damage associated with the lead exposure has proved ineffective, the National Institute of Environmental Health Sciences announced today. Walter Rogan, M.D., of NIEHS, and colleagues from the Treatment of Lead-exposed Children Trial (TLC) reported the results in The New England Journal of Medicine (May 10). The TLC study showed that, as expected, drug treatment with succimer lowered blood lead faster than placebo. Treating lead-exposed two-year-olds, however, did not improve scores on psychological, behavioral and IQ tests when the children were followed until age 5 years.

Succimer remains as the only drug given by mouth labelled for treating children with high blood lead levels. But the hope behind the study was that otherwise symptom-free children exposed to just enough lead to have affected their psychological, behavioral and intelligence tests, might be aided.

NIEHS Director Kenneth Olden, Ph.D., said, "For more than twenty years, NIEHS has sponsored much of the research showing that lead at these levels was harmful to children's brain function, and that succimer lowered blood lead. We had hopes that the treatment would prevent or reduce lead-induced damage in these children, who are mostly poor, African-American, and living in deteriorated housing in big cities. The results of the trial show clearly that treatment after the fact does not undo the damage among 5 year olds. We must prevent these children from being exposed in the first place."

TLC was sponsored by NIEHS and the Office of Research on Minority Health, both of the National Institutes of Health, and the Center for Environmental Health of the Centers for Disease Control and Prevention. McNeil Consumer Products, who produced succimer as Chemet when the study began, provided succimer and placebo. Chemet is now owned by Sanofi-Synthelabo, New York, N.Y. TLC was carried out at four urban teaching hospitals:

The Kennedy Krieger Institute in Baltimore, Md., The University of Cincinnati in Cincinnati, Ohio, The University of Medicine and Dentistry of New Jersey, working with children in Newark, and Children's Hospital, Philadelphia, Pa. The program was managed from NIEHS and the Harvard School of Public Health.

For the study, the Centers for Disease Control and Prevention measured blood lead and the Public Health Service Supply Service Center in Perry Point, Md., provided pharmacy services.

In the early 1990s, when the study was started, it was known that children exposed to more lead had lower scores on IQ tests and that succimer could lower lead levels in blood. It was not known whether using it prevented or reduced the effects of lead on test scores. About 780 children were enrolled between 1994 and 1997. Half were given succimer and half an identical capsule without active drug.

In addition, all the children's homes were cleaned of lead dust, they were given a mineral supplement, and their blood lead was followed. Detailed testing of their cognitive development, neuropsychological function, and behavior was done at three years of follow up. This is a time when the children are old enough to be given sophisticated tests (they were then about 5 years old) and it is the age at which there is the strongest evidence for an effect of lead. While the children given succimer had more rapid drops in their blood lead, the differences in tests scores were small, inconsistent, and not statistically significant, the investigators said. The study was large enough to have detected an improved IQ score of less than 3 points, and no such improvement was seen.

Side effects were relatively infrequent in both groups, but the children given succimer had an unexpectedly higher rate of injuries, which is so far unexplained.

Based on these data, Rogan said, there is little reason to recommend chelation for children with exposures below the current recommendation of 45 mg/dL. Children generally have no symptoms below that level. Succimer remains the recommended therapy for outpatient treatment of children above that level.

The children who participated in TLC are being followed for an additional two years to see if some benefit emerges. In an Australian study, children whose blood leads fell faster without treatment when they were two years old had better IQ test scores when they were seven years old, and 7 year old children attend school and read and so can be tested more extensively.

Although lead poisoning in the US has declined dramatically since the removal of lead from gasoline, in 1998 about 8% of screened children still had blood lead levels that CDC defined as elevated, and about 1% of screened children had a blood lead level high enough to have been eligible for the TLC trial. Lead poisoning is concentrating now among poor children who are eligible for Medicaid and live in deteriorating, inner city housing.

For more information, see the TLC website at http://dir.niehs.nih.gov/direb/tlc1/home.htm.


Story Source:

The above story is based on materials provided by NIH/National Institute Of Environmental Health Sciences. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute Of Environmental Health Sciences. "Drug Treatment Of Lead-Exposed Children Does Not Improve Psychological Test Scores." ScienceDaily. ScienceDaily, 10 May 2001. <www.sciencedaily.com/releases/2001/05/010510072618.htm>.
NIH/National Institute Of Environmental Health Sciences. (2001, May 10). Drug Treatment Of Lead-Exposed Children Does Not Improve Psychological Test Scores. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2001/05/010510072618.htm
NIH/National Institute Of Environmental Health Sciences. "Drug Treatment Of Lead-Exposed Children Does Not Improve Psychological Test Scores." ScienceDaily. www.sciencedaily.com/releases/2001/05/010510072618.htm (accessed September 2, 2014).

Share This




More Mind & Brain News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
Coffee Then Napping: The (New) Key To Alertness

Coffee Then Napping: The (New) Key To Alertness

Newsy (Aug. 30, 2014) Researchers say having a cup of coffee then taking a nap is more effective than a nap or coffee alone. Video provided by Newsy
Powered by NewsLook.com
Young Entrepreneurs Get $100,000, If They Quit School

Young Entrepreneurs Get $100,000, If They Quit School

AFP (Aug. 29, 2014) Twenty college-age students are getting 100,000 dollars from a Silicon Valley leader and a chance to live in San Francisco in order to work on the start-up project of their dreams, but they have to quit school first. Duration: 02:20 Video provided by AFP
Powered by NewsLook.com
Baby Babbling Might Lead To Faster Language Development

Baby Babbling Might Lead To Faster Language Development

Newsy (Aug. 29, 2014) A new study suggests babies develop language skills more quickly if their parents imitate the babies' sounds and expressions and talk to them often. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins