USPSTF: Insufficient evidence to screen asymptomatic pregnant women, young children for elevated blood lead levels

The U.S. Preventive Services Task Force recently concluded there is insufficient evidence to determine the balance and harms of screening for elevated blood lead levels in asymptomatic pregnant women and children aged 5 years and younger.

Elevated blood levels — defined by the CDC as 5 μg/dL — may cause irreversible damage to the central nervous, hematopoietic, hepatic and renal systems; spontaneous abortion and increased BP, cognitive deficiencies, premature birth and reduced fetal growth in young children, Amy G. Cantor, MD, MPH of Oregon Health & Science University and colleagues wrote in JAMA.

The USPSTF wrote there are research gaps in this subject area, specifically: assessments of effective interventions for reducing blood lead levels in pregnant women and adequately-sized evaluations of the effectiveness of treatments for elevated blood lead levels; reports indicating intermediate and health outcomes, outcomes in newborns and harms in women and infants; benefits of nutritional supplementation in reducing blood lead levels in children; point-of-care tests that contain intraindividual and interlaboratory reliability to assess screening strategies in children and pregnant women; questionnaires that recognize different, emerging sources of lead exposure in at-risk communities, screening and prevention methods in these locations and validations of potential risk factors in specific geographic locations and among at-risk populations.

The USPSTF also wrote that not all medical societies’ recommendations align with theirs.

The American Academy of Family Physicians recommends against routine screening for elevated blood lead levels in asymptomatic children aged 1 to 5 years at average risk and pregnant women without symptoms, and that there is insufficient evidence regarding screening in children at increased risk.
The AAP recommends screening based on federal, state, and local requirements; in children residing in communities where 25% or more of housing was built prior to 1960, or there are blood lead levels of 5 μg/dL or higher in 5% or the population or more; in children with identified lead hazards or living in a home constructed before 1960 that is in poor repair or renovated within the previous 6 months; and in immigrant, internationally adopted or refugee children.
CDC and the American College of Obstetricians and Gynecologists recommend targeted screening during pregnancy and lead testing in pregnant and lactating women with one or more risk factors for lead exposure such as pica or occupational or environmental exposures.
CDC recommends screening in children at increased risk for lead exposure.

Adam J. Spanier, MD, PhD, MPH of the University of Maryland School of Medicine and colleagues acknowledged the research gaps and differing points of view among medical societies in a related editorial.

“For clinicians and child health advocates, the USPSTF recommendation could be viewed as disappointing. However, it might be more appropriate to highlight that this determination

regarding screening for lead levels resulted from the complexities of the system,” they wrote. “Hopefully, third party payers will consider factors beyond the USPSTF review in determining policies for reimbursement.”

Spanier and colleagues added that while a USPSTF determination of insufficient evidence is not synonymous with unnecessary, it could act as a springboard that directs future decisions in this area.

“The statement should serve as rationale for funding agencies to direct resources to the gaps in the literature regarding screening and intervention. It also should encourage clinicians and policy makers to review guidance of other organizations, including state and local public health departments, that might use differing methods for evidence evaluation,” they wrote. – by Janel Miller

References: Cantor AG, et al. JAMA. 2019;doi:10.1001/jama.2019.1004.

Spanier AJ, et al. JAMA. 2019;published online ahead of print.

USPSTF. JAMA. 2019;doi:10.1001/jama.2019.3326.

Disclosures: Cantor and Spanier report no relevant financial disclosures. Please see the studies for the other authors’ and USPSTF website for the task force members’ relevant financial disclosures.