Children who have abnormally high blood levels of lead need follow-up testing to see if the problem has improved, but a lot of kids don't get rescreened, says a new study in The Journal of the American Medical Association.

About 434,000 U.S. children aged 1-5 years have blood levels of lead that are too high (10 micrograms per deciliter of blood), says the CDC's web site on lead.

Lead poisoning can cause learning disabilities, behavioral problems, and, at very high levels, seizures, coma, and even death, says the CDC. Symptoms of lead poisoning in children can include fatigue, crankiness, and stomachaches. However, usually there are no signs and the best way to diagnose lead poisoning is a blood test for lead.

Children younger than 6 years old may be at risk because they're growing rapidly and tend to put their hands or other objects into their mouths, says the CDC. A simple finger prick or a small amount of blood taken from the vein can determine blood lead levels.

Major lead sources are lead-based paint and lead-contaminated dust in deteriorating buildings, says the CDC. Lead-based paints have been banned in the U.S. since 1978 but may linger on old walls.

'Too Little, Too Late'

The new study tracked nearly 3,700 Michigan children with abnormally high blood lead levels. All were enrolled in Medicaid.

Only 54 percent had their blood lead levels retested within six months, say the researchers, who included Alex Kemper, MD, MPH, MS, of the University of Michigan. Follow-up blood testing was less likely for Hispanic or nonwhite children, kids from urban areas, and those living in high-risk areas for lead.

"The rate of follow-up testing after an abnormal screening blood lead level was low, and children with increased likelihood of lead poisoning were less likely to receive follow-up testing," says the study.

That's "too little, too late," says a journal editorial by Bruce Lamphear, MD, MPH, of Cincinnati Children's Hospital Medical Center.

Missed Opportunities

More than half of the children (59 percent) who did not get follow-up tests had seen at least one health care worker during the six-month period. But in many cases, they didn't go to their primary provider, so doctors may not have realized that a follow-up lead test was needed.

That's a sign of "a fragmented healthcare system," writes Lamphear, who has served as an expert witness in Rhode Island's lawsuit against the lead industry, says the journal.

Every state handles lead testing differently, so Michigan's results might not be typical, say Kemper and colleagues.

Is Your Home at Risk?

"Approximately 24 million housing units in the U.S. have deteriorated lead paint and elevated levels of lead-contaminated house dust," says the CDC. "More than four million of these dwellings are homes to one or more young children."

Low-income families live in many of the homes at high risk for lead problems. However, wealthier people may also encounter lead in renovating old homes.

Lamphear calls for required screening of high-risk, older housing units before occupancy and after renovation or abatement.

Less common sources of lead exposure include making stained-glass windows and recycling or making automobile batteries, says the CDC.

The CDC also says lead pipes, solder, brass fixtures, and valves can leach lead and that most lead in household water comes from plumbing in the house, not the local water supply.

Some home health remedies and cosmetics may contain lead. According to the CDC, these include: arzacon and greta, which are used for upset stomach or indigestion; pay-loo-ah, which is used for rash and fever; and the cosmetics kohl and akohl.

What to Do

Concerned about children's lead risk? The CDC offers this advice:

—Ask a doctor to test your child's blood lead level.
—Talk to your state or local health department about testing paint or dust from your pre-1978 home.
—Reduce exposure to lead by cleaning floors with a damp mop, swabbing surfaces with a damp wipe, and frequently washing a child's hands, toys, and pacifiers.
—Use only cold water from the tap for drinking, cooking, and making baby formula. Hot tap water is more likely to contain higher levels of lead.
—Avoid using home remedies and cosmetics containing lead.
—If you remodel buildings built before 1978 or work with lead-based products, take steps to reduce your lead exposure. For instance, shower and change clothes when you're done with a task involving lead exposure.

Adequate calcium intake appears to be protective against lead toxicity. It decreases the absorption of lead for the gut. Calcium also prevents exposure to lead during bone metabolism. When lead is ingested it can accumulate in bone.

Vitamin C may also protect against lead toxicity. How this occurs is not fully understood, but it is believed to inhibit lead absorption as well as increase the excretion of lead in the urine.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Kemper, A. The Journal of the American Medical Association, May 11, 2005; vol 293: pp 2232-2237. Lamphear, B. The Journal of the American Medical Association, May 11, 2005; vol 293: pp 2274-2276. CDC: "General Lead Information: Questions and Answers." Linus Pauling Institute.