CDC Advisory Panel States Lead Levels Greater Than 5 mcg/dL Are Abnormal and Dangerous

Article Review:

In January of this year, CDC advisory panel established lower threshold cutoff for blood lead levels to5 mcg/dL.  Previously,lead levels over 9.9 mcg/dL were considered abnormal. 

G. Patrick Daubert, MD, a toxicologist with the KPNC Regional Toxicology Service, sent out an email to all physicians in February 2012 explaining the rationale for the change acceptable blood lead levels.

Studies have shown that children with lead levels 5 – 10 mcg/dL can have occult deficits in their IQ.  Furthermore, this finding has also been shown in independent studies throughout the world examining children age 5 years and older.  Thus, the new recommendation calls for intervention with blood lead levels greater than 4.9 mcg/dL.

Highlights of the CDC’s recommendation to Pediatricians are as follows:

·        All children between the ages of 6 months and 3 years should be screened for pica and environmental lead exposure risks.

·        The Public Health Department, in most cases, is able to investigate dwellings that may pose a risk for lead exposure to infants and children.

·        If there is a risk of lead exposure or pica by history, children should have a blood lead level done at 1 and 2 years of age.

·        High risk groups for elevated blood lead levels include immigrants, international adoptees, and children whose parents work with lead products.  In addition, children who live in a home built prior to 1978, which is undergoing renovations and/or has peeling paint or paint dust, should be considered high risk and tested.

Editor’s Commentary:
 

In 2009, the California Department of Public Health reported that 642,526 children ages 0 to 5 years were tested for blood lead levels.  Of these, 2426 (0.4 %) had lead levels greater than 9.5 mcg/dL.  The counties of Lassen, Modoc, and Mariposa represented the highest prevalence of elevated lead with 3.6%, 2.5%, and 2.3% respectively.   Among this group, 22,876 (3.6%) children age 0 to 5 years had elevated lead levels 4.5–9.5 mcg/dL.  Sierra, Mono and Modoc counties represented the highest levels at 23.5%,  16.5% and 11.8% respectively.

Once a child is identified as having a blood lead level over 5 mcg/dL, it is unclear how effective the public health department can be in eliminating the lead exposure without removing the family from their current dwelling.  In addition, there is no evidence that chelation improves the child’s cognitive deficits already imposed by the lead exposure.

Children with an elevated lead level should be referred via eConsult to the Toxicology service in San Jose or South Sacramento.  Specialists from those departments will evaluate each case by TAV or in the clinic if deemed appropriate.

Commentary from G. Patrick Daubert, MD,, KPNC Regonal Toxicology

The CDC and others have been talking about this change for a long time, especially when Lanphear's studies and others showed neurocognitive deficits in children with lead levels < 10 mcg/dL.  The conclusion from these studies was that there was really no threshold level for lead toxicity.  The threshold "levels" for lead toxicity or concern, if you will, have decreased since the 1960s from 60 mcg/dL to 25 mcg/dL to 20 mcg/dL to 10 mcg/dL.  These decreases were done primarily as a public health measure, rather than defining a lead level for which medical intervention, e.g. chelation therapy, was needed. 

 We should all think of plumbism as a social disease. Clinicians have a major role in identifying children at risk but only a minor role in evaluation and possible chelation. The real resources needed are public health. Over the past 30-40 years, the rationale and subsequent resources invested for doing environmental/home assessments and somewhat more comprehensive medical assessments (development, diet, etc.) has significantly increased in most areas, in an effort for more primary prevention. 

 In the Midwest and Northeastern U.S. lead poisoning is primarily due to lead paint exposure/ingestion, often associated with pica and iron deficiency anemia, In California, lead exposure is often due alternative medicines, exposure to lead-containing products such as pots, plate or other cookware and less commonly, lead-based paints. Children that are part of the WIC program will likely get blood lead levels drawn. In children not enrolled in WIC program, lead screening should be performed with unexplained iron deficiency anemia, pica behavior, use of home/tradition remedies (more common in Hispanic and Asian communities), and parents whose occupation involves lead exposure.

 I don't think that lowering the threshold from 10 to 5 mcg/L will necessitate any significant change in medical evaluation or therapy on the clinician’s part. Our regional lab already informs us of all the positive lead results (currently > 5 mcg/dL) each week. In addition, all positive results are automatically sent to the California Department of Public Health, which in turn communicates with the local health departments. Our service already works closely with several of the county public health departments. Our goal is to offer our services in any way we can to aid in the evaluation and management of children with lead poisoning. We hope to work closely with our pediatrician colleagues in these cases.

In addition, we are happy to take on these cases if you would prefer. You can send an eConsult to the Toxicology service in San Jose or South Sacramento.