Dear Dr. Lanny: My baby girl is due for a blood draw to test for lead at her 12-month doctor’s visit. I am not looking forward to this. Why do they have to take blood? I’m also little concerned about the results because we live in an old house. (Our daughter seems to be developing normally, according to her pediatrician.) Can you tell me about the lead test?
A: Humans and lead have a long history together. Lead beads have been found in Turkey dating from before 6,000 B.C. Lead’s uses are many and varied, including radiation shielding, paint colorants, manufacture of organ pipes and fine crystal glassware. Lead is also found in a number of traditional medications around the world.
Lead, however, has no purpose in the human body, and any lead in our blood or tissues can be considered a contaminant. Over the past several decades the “acceptable” level of lead in blood has decreased from 60, to 40, to 25, to 10. Present thinking is that there is really no “OK” level for lead. There is virtually no place on Earth that does not have some lead contamination.
Despite the remarkably widespread presence of lead in our environment, and the increasing uses of lead throughout industry, this story has moved in a very positive direction.
The two most significant sources of lead in the United States have been leaded paint and leaded gasoline. Lead has a number of benefits in the production of paint, including faster drying and increased durability. As early as the beginning of the 20th century, however, lead in paint was recognized as a danger, and it was banned in some European countries. In the United States, it was not until the late 1970s that regulations strictly curtailing the use of lead paint were put into effect.
Decreasing lead in house paint has been a giant step toward eradicating lead poisoning in children. Whole zip codes have been built since lead was no longer allowed in paint and, as communities, are at no significant risk for lead poisoning. And yet there are still countries where leaded paint continues to be sold.
Although it is not a commonly recognized occurrence, your pets, particularly kittens or puppies, are also at risk in a lead-contaminated house.
Everyone is aware of the danger of flaking and peeling paint in homes built before 1978, but fewer think about the danger associated with renovating older homes or even the progressive deterioration of apparently stable painted surfaces.
The second major source of lead in the United States was leaded gasoline. Tetraethyl lead was first put into use in the 1920s and soon became standard in gasoline. Ethyl, as it was originally known (to prevent people from realizing that it contained lead), improved the performance of automobile engines. Its toxicity was quickly noted, but felt to be limited to those with workplace exposure. Others questioned this “limited danger” theory, but lobbying efforts and industry pressure allowed leaded gas to be sold for decades. Not until 1976 did the United States begin a multiyear phase-out of leaded gasoline. Unfortunately, as with lead paint, leaded gasoline continues to be sold in different parts of the world, with large amounts of lead still being released into the air.
The combination of the removal of lead from gasoline and paint has had a remarkable effect on the levels of lead in children’s blood. National health studies showed a 78 percent decline in average lead levels from the early 1970s to the early 1990s. That decline continues for the population as a whole, although children living in old and substandard housing still remain at significant risk.
There have been other sources of lead contamination, including certain imported toys, vinyl mini-blinds, and certain types of pottery. These, and other minor sources, may prevent total eradication of lead poisoning, but at present, lead paint from old homes remains our greatest concern.
New York state regulations require children to have their blood tested for lead at 1 and 2 years of age. Further testing is done if the child has been shown to be at high risk. It is possible that future recommendations may be more targeted given that new communities and developments may have no likely source of lead.
Children’s blood may be tested by either venipuncture (taking blood from a vein) or by a capillary sample (finger or heelstick). The American Academy of Pediatrics recommends venipuncture, as it is the more accurate method, but finds fingerstick a practical alternative.
If your home was built after 1978, there is little likelihood of lead poisoning. If it was built before 1978 but has been well maintained, without obvious peeling of old paint, you are probably fine as well. If the home, however, is older and shows flaking or peeling of deeper layers of paint, blood lead testing will show if there are any actual or developing problems. Treatment of elevated blood lead is only required in a small number of children. I would hope that never becomes necessary for you, and would leave that discussion to you and your doctor.
Dr. Alan Freshman, father of two grown boys, practices at Syracuse Pediatrics. Consult your own physician before making decisions about your family’s health care. Send e-mail to him at firstname.lastname@example.org.