Draft Recommendation Statement

USPSTF: More Research Needed on Screening for Lead Exposure

November 07, 2018 03:38 pm Chris Crawford

Lead exposure can seriously damage the health of children during their entire lifetime, with elevated amounts of lead in the body adversely affecting organs and organ systems, including the nervous system, heart, kidneys and liver.

[lead free kids poster]

High lead levels in children can cause behavioral and learning problems, lower IQ, hyperactivity, impaired growth, hearing problems, anemia and even death. For pregnant women, high lead levels can cause miscarriage, early delivery, low birth weight and maternal hypertension.

On Oct. 30, the U.S. Preventive Services Task Force (USPSTF) posted a draft recommendation statement(www.uspreventiveservicestaskforce.org) and draft evidence reviews on screening for elevated blood lead levels in children(www.uspreventiveservicestaskforce.org) and pregnant women.(www.uspreventiveservicestaskforce.org)

Based on its review, the USPSTF said current evidence is insufficient to assess the balance of benefits and harms of screening for elevated blood lead levels in children and pregnant women who are asymptomatic; both are "I" statements.(www.uspreventiveservicestaskforce.org) 

Story Highlights
  • The U.S. Preventive Services Task Force (USPSTF) said current evidence is insufficient to support routine screening for elevated blood lead levels in children and pregnant women who are asymptomatic.
  • The task force found that although blood tests can detect elevated levels of lead in the blood, questionnaires to identify patients at risk are less effective, and treatments cannot reverse many of the effects of exposure.
  • This draft recommendation statement updates the USPSTF's 2006 recommendation, which recommended against screening in children at average risk and pregnant women but also called for more research.

The task force found that although blood tests can detect elevated levels of lead in the blood, questionnaires to identify patients at risk are less effective, and treatments cannot reverse many of the effects of exposure.

"There is no safe level of lead in the blood. Finding and removing sources of lead in the environment that might affect children is essential," said USPSTF member Alex Kemper, M.D., M.P.H., M.S., in a news release.(www.uspreventiveservicestaskforce.org) "The task force is calling for more research so clinicians can have better screening tools and effective treatments to help prevent health problems that can result from lead exposure."

This draft recommendation statement updates the USPSTF's 2006 recommendation,(www.uspreventiveservicestaskforce.org) which found that the evidence was insufficient to recommend for or against screening for lead exposure in children at increased risk, but recommended against screening in average-risk children and asymptomatic pregnant women. That recommendation statement also called for more research to determine the efficacy of screening.

The AAFP supported the task force's final recommendation at the time.

Family Physician's Perspective

Paul Lazar, M.D., attending physician at McLaren-Flint Family Medicine Residency in Flint, Mich., pointed out that the USPSTF actually upgraded its recommendation from a "D" statement against routine screening for elevated blood lead levels in 2006 to the current "I" draft statement citing insufficient evidence to assess the benefits and harms of screening.

"I think they realize this is a decision we probably need to make based on our populations and communities," he told AAFP News.

Lazar has seen firsthand the devastating effects lead poisoning can have on patients and a community, with the city where he lives and practices having experienced lead contamination in its water supply since April 2014.

The contamination occurred after water department officials made the cost-saving decision to change the city's water source from Lake Huron to the Flint River and ran the water through old pipes.

Flint switched back to the previous source in 2015, but the damage was already done.

"We have seen tons of people who are afraid or have symptoms that may or may not be due to lead," said Lazar. "We've had lots of people with skin rashes that we think are probably because the city had to add extra chlorine to the water because there was a high coliform count. This was more irritating to the skin. Imagine taking your bath in the swimming pool instead of your bathtub with regular tap water."

Lazar said he continues to recommend that his patients not drink local Flint tap water or cook with it.

As a Flint homeowner himself, Lazar drank tap water during the period the state government denied it was harmful.

"I turned on my taps once and the water was running reddish-brown rust color," he said. "You could definitely tell there were particulates in it."

Additionally, Lazar said Flint experienced regular water main breaks during the crisis, including in his neighborhood, that are thought to have been due to the corrosiveness of the water. This has slowed the plan to replace all water lines in the city.

Another issue spurred by the Flint water crisis is that children aren't getting the right amount of fluoride in their drinking water because they're drinking bottled water instead, which may or may not contain fluoride.

"So, I'm thinking we're probably going to have more problems with tooth decay and other related issues," Lazar said.

Adding another barrier to Flint residents' health, the state stopped shipping free bottled water to the area in April of this year, when Gov. Rick Snyder declared the city's water supply safe to drink. But most residents still don't consider tap water a viable alternative yet.

Syed Zaidi, M.D., of Grand Blanc, Mich., was a 2018 Family Medicine Experience poster winner for his residency project, "Aftermath of the Flint Water Crisis," which is examining the behavioral aspects and fears that community members still have about the water and how it affects their lives.

Zaidi's observational study, which is being conducted at the same facility in which Lazar practices, is asking 400 clinic patients to complete a questionnaire with demographic data and attitudes and behaviors they have about various aspects of the Flint water crisis. The data will be analyzed to determine the prevalence and severity of somatic symptom disorder and illness anxiety disorder caused by the public health crisis.

"So far, the findings have been that people are afraid of the water and not using it for the purposes it's said to be safe for," Lazar said.

Recommended Best Practices

Lazar offered some thoughts on what he considers best practices to help prevent lead poisoning.

First, he said, cities with water systems dating before the 1920s (when lead pipes were in common use) should consider population-based screening for lead in the blood.

"But also press your water departments to give free water testing for home taps, with correct sample collection instructions," Lazar said.

The Environmental Protection Agency requires cities to send reports of any positive samples for lead in community water.

"If there are any positive samples for lead in community water tests, that would be an indication to consider screening kids in that area for blood lead," Lazar said. He noted that his practice has been offering blood lead testing liberally since the water crisis began in Flint and has seen a couple of positive results.

As for screening questionnaires for patients, Lazar recommended using them to identify at-risk populations such as urban, underserved children and those who have higher exposure to lead-based paint residue because they live in older homes or apartments.

He also recommended screening kids who regularly drink well water, because lead is a naturally occurring component of soil. This advice also applies to infants whose formula is made using well water or whose mothers breastfeed while drinking well water.

Lazar said an issue with blood-based lead screening is that blood level elevation is transient with acute exposure, which is why he thinks the USPSTF found insufficient evidence to support the practice.

"The lead doesn't stay in the blood -- it's not that soluble; it goes into bones, teeth, liver and the brain," he said.

Finally, Lazar emphasized that testing for blood lead levels is a decision that should be made by individual clinicians in concert with their patients, and they should consider the local patient population, potential exposure to lead and water testing in their community.

Up Next

The USPSTF is inviting comments on its draft recommendation statement(www.uspreventiveservicestaskforce.org) and draft evidence reviews for children(www.uspreventiveservicestaskforce.org) and pregnant women(www.uspreventiveservicestaskforce.org) on screening blood for lead levels.

The public comment window for the draft recommendation is open until 8 p.m. ET on Dec. 3. All comments received will be considered as the task force prepares its final recommendation.

The AAFP will review the USPSTF's draft recommendation statement and supporting evidence and provide comments to the task force. The Academy will release its own recommendation on the topic after the task force finalizes its guidance.

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