The American Academy of Pediatrics (AAP) is asking the US government to change their policy on lead exposure and toxicity in children. The recently published new AAP policy statement, Prevention of Childhood Lead Toxicity formulated by Dr. Bruce Perrin Lanphear, MD, MPH, FAAP, claims that even very small levels of lead in the blood of children are not safe. For that reason there is an imminent need by the government to renew efforts for prevention of lead exposure in children.
The World Health Organization (WHO) states, “There is no known safe blood lead concentration.”
Lead is a toxic metalloid and its accumulation in the human body can damage multiple organs, especially in young children. According to official guidelines, blood lead levels (BLLs) below 5 micrograms per deciliter are deemed safe or harmless. However an increasing number of research data has shown that even 5 µg/dL or 50ppb levels of lead in children can negatively affect their intellectual and academic abilities. Such low levels of lead are also believed to cause attention-deficit or hyperactivity disorder as well as a low birth weight. In such cases, unfortunately, there is no known treatment for reversing the damaging effects of lead on the development of children.
The updated policy by AAP has outlined recommendations and measures for both government and for physicians in the public health sector, to limit lead exposure.
“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,” said Dr. Lanphear.
WHO estimates that every year more than 600,000 children suffer from intellectual disabilities due to lead poisoning. Exposure of children to lead can damage the brain and the central nervous system, slow growth and development, cause learning and behavior disorders e.g. ADHD and cause hearing and speech retardation. Children can be exposed to lead from living in contaminated houses, from soil and water or from lead-containing consumer products e.g. cosmetics.
While sharing his views, Dr. Leland McClure, PhD and Fellow of the American Board of Forensic Toxicology said, “The U.S. has made progress in reducing the burden of lead toxicity. But this public health success story is incomplete. […] areas with high rates of pre-1950s housing construction and low incomes were associated with larger proportions of children with high blood lead levels.”
Lead concentrations in the US have reduced dramatically among children over the last four decades however a number of them still live in houses contaminated with the toxin. Between 2007 and 2010 more than 2.6% equal to 535,000 of pre-school aged (1 to 5 years old) children were found to have a blood lead concentration greater than the currently accepted level; 5 µg/dL. A large majority of these children live in houses built during the 1950s which are covered with deteriorated lead-based paint and are the major sources of exposure to lead.
In its updated policy, the AAP Council on Environmental Health agreed upon primary prevention i.e. removing sources of lead from the environment before child exposure occurs, is the most cost-efficient way of preventing childhood lead toxicity. Otherwise children with a BBL ≥5 µg/dL are expected to encounter an IQ decrease of 5-6 points. Although a five point deficit may not seem much to some, the shift means that the IQ level as a whole in American children will fall dramatically. For instance, the number of American children with an IQ lower than 70 will increase from 6 million to 9.4 million.
“Low-level elevations in children’s blood lead concentrations, […] can result in decrements in cognitive functions, as measured by IQ scores and academic performance,” said Dr. Lanphear.
The policy estimated that every $1 invested in lead-contaminated houses for renovations to reduce exposure will save $17 to $221 from lead poisoning-related adverse effects. Parents expecting their first child are advised to screen their home for lead sources if it was built before 1978, especially poorly maintained houses.
Similarly, health experts such as pediatricians and other primary care workers need to screen and monitor children for lead poisoning in the first three years of their lives, particularly children who live in low-income areas. Furthermore only blood tests with a lab error of ±2 µg/dL should be used for detecting BLL. The policy also proposes the US government provide both financial and non-financial resources to state and local health agencies to prevent exposure to lead.
Lead poses more danger to the health of younger children since they can ingest four to five times more of the toxin than adults, due to behavior such as mouthing and swallowing of lead-contaminated objects. If lead enters the body it can travel to organs such as brain, kidneys, liver and bones to cause them extensive damage. Likewise children from impoverished communities are more susceptible to lead since their bodies lack other nutrients and absorb the toxin more readily. High levels of lead in children can even result in coma, convulsions or death.