Friday, June 24, 2016

Lead toxicity in childhood

A new policy statement from the Council on Environmental Health of the American Academy of Pediatrics (AAP) aims to prevent lead toxicity in US children.

The statement, published online June 20 in Pediatrics, especially targets US preschoolers who have lead blood level concentrations of 5μg/dL or higher. Although both mean blood lead levels and the prevalence of high blood levels have dropped during the last 4 decades, the National Health and Nutrition Examination Survey found that in 2007 to 2012, about 2.6% of preschoolers, or 535,000 children aged 1 to 5 years, had lead levels at or above this threshold.

No blood lead concentration is considered safe. "Blood lead levels in children have declined dramatically, but new studies have shown that lead exposure still accounts for 24 million lost IQ points and about one in five cases of attention-deficit hyperactivity disorder in US children," lead author Bruce Perrin Lanphear, MD, MPH, a professor of health sciences at Simon Fraser University in Burnaby, British Columbia, Canada, told Medscape Medical News. "Lead has been phased out or banned in gasoline, paint, and water pipes, but children continue to be exposed to the lead remaining in their environment, particularly in paint, dust, soil, and water in and around their homes."

The risk for exposure is greatest in the first 2 years of life, and there are no effective treatments for the permanent developmental and cognitive effects of lead toxicity. The estimated annual cost of childhood lead exposure in the United States is $50 billion, according to the APA document.

"For every $1 invested to reduce lead hazards in housing units, society would benefit by an estimated $17 to $221, a cost– benefit ratio that is comparable with the cost–benefit ratio for childhood vaccines," the statement notes, citing a 2009 study.

According to previous research by Dr Lanphear and colleagues, lead dust is the greatest driver of elevated blood concentrations in children, accounting for almost 40% of the increase, followed by water lead, at nearly 20%.

Other sources of exposure are industrial emissions, transmission from parental worksites, the water supply, food, costume jewelry, toys, ceramics, folk medicines, cosmetics, and various consumer products that slip through the regulatory cracks.

According to the policy paper, pediatricians are well positioned to make a difference. In many instances, their clinical histories can provide important case management information by offering clues to potential contamination sources in patients' living environments. Appropriate management will require investigation of these sources, with a questionnaire and visual inspection for other potential exposures, the statement said.

Although the routine screening questionnaires used in primary care do not detect children with elevated blood lead concentrations, the authors add, they may help identify environmental hazards for children with concentrations of 5 μg/dL or higher (≥50 ppb). In clinical practice, prevention begins with counseling parents to undertake environmental assessments if their housing was built before 1960 and has been recently renovated.

In addition to several funding, monitoring, and regulatory recommendations aimed at government, the policy paper had suggestions for pediatricians and other healthcare providers. Among these:

collaborate with public health officials to regularly survey blood lead concentrations in randomly selected children,

recommend environmental assessments of older housing,

advocate for strict and well-enforced legal standards for allowable levels of lead in common sources,

be familiar with government and professional recommendations for screening children and pregnant women for lead poisoning, and

conduct targeted screening of toddlers ages 12 to 24 months if they reside in housing communities with at least 25% of units built before 1960 or with a prevalence of child blood lead concentrations of 5 μg/dL or higher (≥50 ppb).

"Reducing sources of lead is the most reliable, cost-effective way to protect children," Dr Lanphear said. "We need to provide landlords with incentives, like tax credits, for making their housing units safe, and impose fines if they fail."

But although landlords have often been blamed for the problem, they really just inherited it. "The real culprits are the lead industries who misled us about the dangers of lead. They put their profit over people's health," Dr Lanphear said.



  1. COUNCIL ON ENVIRONMENTAL HEALTH. Prevention of Childhood Lead Toxicity. Pediatrics. 2016 Jun 20.

    Blood lead concentrations have decreased dramatically in US children over the past 4 decades, but too many children still live in housing with deteriorated lead-based paint and are at risk for lead exposure with resulting lead-associated cognitive impairment and behavioral problems. Evidence continues to accrue that commonly encountered blood lead concentrations, even those below 5 µg/dL (50 ppb), impair cognition; there is no identified threshold or safe level of lead in blood. From 2007 to 2010, approximately 2.6% of preschool children in the United States had a blood lead concentration ≥5 µg/dL (≥50 ppb), which represents about 535 000 US children 1 to 5 years of age. Evidence-based guidance is available for managing increased lead exposure in children, and reducing sources of lead in the environment, including lead in housing, soil, water, and consumer products, has been shown to be cost-beneficial. Primary prevention should be the focus of policy on childhood lead toxicity.

  2. In some U.S. cities, at least one in seven kids have unsafe levels of lead in their blood, indicating exposure to a toxic metal that can lead to lifelong physical, mental and behavioral health problems, a recent study suggests.

    According to the Centers for Disease Control and Prevention (CDC), a blood lead level equal to or greater than five micrograms per deciliter of lead in blood is considered unsafe for children.

    Researchers examined more than 5.2 million blood lead level test results for infants and children under 6 years of age over a six-year period ending in April 2015. They found 3.1 percent of boys and 2.8 percent of girls had blood lead levels exceeding what the CDC considers safe.

    In six regions, more than 14 percent of kids had unsafe blood lead levels: Syracuse, Buffalo and Poughkeepsie in New York; Oil City and York in Pennsylvania and Cincinnati, Ohio.

    “Many of these localities are old, industrial cities,” said Dr. Harvey Kaufman, senior medical director at Quest Diagnostics in St. Louis, Missouri, and an author of the study.

    “There are many reasons why these localities could have the highest percentage of children who test with elevated blood lead levels, including more old housing stock, higher poverty rates and possibly fewer resources for remediation of older housing,” Kaufman added by email.

    Even though lead was phased out of paint in the 1970s, many children in communities with older housing stock are still at risk for lead exposure because these buildings haven’t been inspected for lead or because the metal hasn’t been removed where it’s found, said Dr. Leonardo Trasande, a pediatrics researcher at New York University School of Medicine who wasn’t involved in the study...

    The study also identified five states with the largest proportion of tests indicating high blood lead levels: Minnesota (10.3 percent), Pennsylvania (7.8 percent), Kentucky (7.1 percent), Ohio (7.0 percent) and Connecticut (6.7 percent). California and Florida had the lowest rates, with 1.4 percent and 1.1 percent, respectively.

    Over the course of the study, the proportion of children with high blood lead levels nationwide dropped slightly, from about 3.7 percent to 2.6 percent.

    Even blood lead levels lower than the CDC threshold for unsafe exposure to the toxic chemical may put children at risk for reduced intellectual and academic abilities and attention deficit hyperactivity disorder, according to the American Academy of Pediatrics (AAP).

  3. Elevated lead levels have been found in water in five more Chicago public schools, bringing to 19 the number of buildings where tests have uncovered levels that exceed a federal standard of 15 parts per billion.

    Chicago Public Schools officials say the district has tested water at 224 of 324 school buildings that were constructed prior to 1986. So far, the district said it has received test results for 74 schools.

    In the latest results, water from one sink at the Blair Early Childhood Center, a specialty school for disabled children between the ages of 3 and 6, showed lead levels as high as 1,100 parts per billion, while the water fountain showed levels as high as 357 parts per billion.