Rochester Scientist Leads National Fight against Lead

Jan. 12, 2012
Deborah Cory-Slechta, Ph.D.

When the U.S. Centers for Disease Control and Prevention needed a scientist to lead the panel charged with making recommendations regarding hazardous levels of lead in children, they turned to one of Rochester’s own.

Deborah Cory-Slechta, Ph.D., professor of Environmental Medicine and an internationally recognized authority on the hazards of lead, was co-chair of the CDC panel that last week recommended slashing the level of lead that should be considered as the point for intervention by physicians and public health authorities.

The main message of the recommended guidelines put forth by Cory-Slechta and colleagues, however, isn’t about the precise levels of lead in the blood that should be considered “safe” or “unsafe.”

Rather, she states unequivocally, “With lead, there is no safe level. It’s that simple.”

But as patients, physicians and public health agencies across the nation clamor for guidance about how best to approach the pervasive problem, it’s clear that guidelines are needed. So while the panel states clearly that any measurable amount of lead damages the body, it made the decision to put the “action point” at 5 micrograms of lead per deciliter of blood – just half the number that has been in place since 1991.

While estimates vary in the number of children who need to have their lead levels lowered immediately, estimates under the current rule put that number at approximately 250,000. The new measure, if adopted by CDC, would nearly double that number, to 450,000.

“While no level is safe, we do need a number that people can cite to help give them direction about when action is needed,” said Cory-Slechta. “For instance, with current level, many pediatricians would tell families whose children who had some lead but whose level was below 10 that their children were fine. But, there really is no safe level. Reducing the action level is one way of increasing the number of children who will be protected more forcefully.”

Cory-Slechta was an author of a groundbreaking 2003 paper in the New England Journal of Medicine that showed without question that lead levels below the current cutoff damage the brains of young children, hurting their ability to think, plan, and learn. Her team even showed that a lot of damage appears to occur at these very low levels – that while a child’s health certainly worsens as the lead level rises, that even small amounts do a great deal of damage.

The latest action comes nearly four decades after lead was eliminated from gasoline and more than 30 years after lead was banned from paint. In the body, lead can substitute for calcium, a mineral crucial to our health. When lead gets in the mix, it damages the brain, hurting our ability to think and learn and causing behavioral problems. High lead levels also hurt pretty much every major organ, causing cardiovascular problems, high blood pressure, and stunting growth, for instance. Lead has even been linked to osteoporosis, since it’s most likely to be taken up and stored in the skeleton.

The level at which lead is considered dangerous in children has fallen over the decades. Fifty years ago, the level was set at 60 micrograms per deciliter – a level which would trigger emergency measures today. The current level of 10 has been in place since 1991, despite many studies showing that damage occurs even below this level. Scientists have consistently found effects at whatever level they’ve been able to measure, which is now in the neighborhood of 2 micrograms per deciliter.

Since the effects of lead are irreversible, Cory-Slechta says prevention is crucial.

The top priority is making sure homes are as free of lead as possible, since paint used in homes build before 1978 is the primary source of lead poisoning in children. Other steps include educating parents about the dangers of lead; testing home lead levels frequently; vigilance on the part of pediatricians asking families when their homes were built; and counseling pregnant women about the dangers to their unborn children. When a child with an elevated lead level is identified, crucial steps include cleaning up lead in that child’s environment, monitoring the child closely, but also checking levels of all children who live in the same building.

“Right now, unfortunately, children really are the canaries in the coal mine. We wait for children to show up to their doctors with elevated blood levels. For those children, it is already too late,” said Cory-Slechta.

Cory-Slechta was a graduate student at the University of Minnesota, in a laboratory focused on research around drug abuse, when she cast about for a project of interest and came across a paper on lead and behavior. Soon she became wrapped up in the subject, and her graduate adviser supported her efforts to explore the new research avenue.

As a young scientist in Rochester in the early 1980s, some of her early results – showing that a common way to remove lead from a child’s body can sometimes cause great harm to children – met with tremendous resistance. She persevered, her science was sound, and a treatment known as chelation is now reserved for only the sickest children.

For more than 20 years, Cory-Slechta has been very influential helping the government develop policies and approaches about environmental hazards. She has advised the National Academy of Sciences, the National Research Council, the Institute of Medicine, the Environmental Protection Agency, and the U.S. Senate about the health effects of lead, plastics, pesticides, air pollution, and chemicals like trichloroethylene. 

“This is how research can really have an impact,” said Cory-Slechta. “It’s my way of giving back to the community, trying to make the science clear and robust so that informed decisions can be made. I’ve been lucky, as I’ve been able to see how my research is making a difference in the world.”