USPSTF: Inconclusive Evidence for Lead Screening in Asymptomatic Children

The US Preventive Services Task Force (USPSTF) has issued a new recommendation stating that there is insufficient evidence to evaluate the benefits and harms of screening for elevated blood lead levels in asymptomatic children and pregnant persons.

The current recommendation is an update to the previous 2006 statement that recommended against routine screening for elevated blood lead levels in asymptomatic children aged 1 to 5 years at average risk or in asymptomatic pregnant persons. Those recommendations were “D recommendation” level, which the USPSTF defines as a service where “there is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.” The current update was issued as an “I statement” for insufficient evidence.

In an accompanying editorial, Adam J. Spanier, MD, PhD, MPH, Pat McLaine, DrPH, RN, and Robyn C. Gilden, PhD, RN, emphasized the importance of recognizing this I statement not as recommendation against the preventive service, but as recognition that the evidence is insufficient to recommend for or against the service.

“The I statement should not be interpreted as sufficient evidence that the service is unnecessary. The statement should serve as rationale for funding agencies to direct resources to the gaps in the literature regarding screening and intervention,” wrote Spanier, McLaine, and Gilden.

In a separate editorial in JAMA Pediatrics, Michael Weitzman, MD, Department of Pediatrics, NYU Langone Health, also called for more rigorously conducted research is necessary to answer the questions that remain about lead screening and preventing lead exposure.

“The inconclusive findings of the new USPSTF recommendation does not mean that screening children for elevated lead levels is not necessary, nor does it shed light on whether screening should be targeted to children at high risk or whether it should be universally done,” wrote Weitzman.

While no studies were found that directly compared the health outcomes of screening versus not screening in young children and during pregnancy, there were a few randomized clinical trials (RCT) that evaluated interventions for elevated blood lead in children. These had mixed results or found no clear effects from nutritional supplementation or home lead abatement.

A single RCT found that calcium supplements were associated with reduced blood lead levels compared with placebo in health pregnant women. The USPSTF noted that no studies were found that dealt with health outcomes in asymptomatic pregnant persons after lead-reduction interventions.

The USPSTF found no studies that evaluated the harms of screening for elevated blood lead levels in children, and just 2 that looked at the harms of treatments. One study deemed good-quality found that treatment with dimercaptosuccinic acid contributed to a small, significant decrease in children’s height growth over 34 months. A poor-quality study of chelation therapy with penicillamine reported adverse events associated with the treatment, including leukopenia, thrombocytopenia, hives and maculopapular rash, urinary incontinence, abdominal pain, and diarrhea. They found no studies that evaluated the harms of screening for or treatment of elevated blood lead in pregnant persons.

Until more research can be conducted to answer questions that remain, the USPSTF report points toward other institutions. These include the American Academy of Family Physicians, which recommends against routine blood lead screening of asymptomatic children at average risk. The American Academy of Pediatrics points towards federal, state, and local screening requirements for screening children living in high-prevalence areas, with identified lead hazards, or children who are immigrants, refugees, or internationally adopted.

For asymptomatic pregnant persons, the American Academy of Family Physicians recommends against routine screening. Both the US Centers for Disease Control and Prevention (CDC) and e American College of Obstetricians and Gynecologists recommend targeted screening during pregnancy and testing for pregnant or lactating persons with ≥1 risk factor.

The USPSTF recommendation, evidence report, and Spanier et al editorial were published in JAMA. The Weitzman editorial, “Blood Lead Screening and the Ongoing Challenge of Preventing Children’s Exposure to Lead,” was published in JAMA Pediatrics.