Carla Campbell

Interpreting and Managing Blood Lead Levels of Less Than 10 μg/dL in Children and Reducing Childhood Exposure to Lead: Recommendations of the Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention

Lead is a common environmental contaminant. Lead exposure is a preventable risk that exists in all areas of the United States. In children, lead is associated with impaired cognitive, motor, behavioral, and physical abilities. In 1991, the Centers for Disease Control and Prevention defined the blood lead level that should prompt public health actions as 10 μg/dL. Concurrently, the Centers for Disease Control and Prevention also recognized that a blood lead level of 10 μg/dL did not define a threshold for the harmful effects of lead. Research conducted since 1991 has strengthened the evidence that childrens physical and mental development can be affected at blood lead levels of <10 μg/dL. In this report we provide information to help clinicians understand blood lead levels < 10 μg/dL, identify gaps in knowledge concerning lead levels in this range, and outline strategies to reduce childhood exposures to lead. We also summarize scientific data relevant to counseling, blood lead screening, and lead-exposure risk assessment. To aid in the interpretation of blood lead levels, clinicians should understand the laboratory error range for blood lead values and, if possible, select a laboratory that achieves routine performance within ±2 μg/dL. Clinicians should obtain an environmental history on all children they examine, provide families with lead-prevention counseling, and follow blood lead screening recommendations established for their areas. As circumstances permit, clinicians should consider referral to developmental programs for children at high risk for exposure to lead and more frequent rescreening of children with blood lead levels approaching 10 μg/dL. In addition, clinicians should direct parents to agencies and sources of information that will help them establish a lead-safe environment for their children. For these preventive strategies to succeed, partnerships between health care providers, families, and local public health and housing programs should be strengthened.

Organic Foods: Health and Environmental Advantages and Disadvantages

The US market for organic foods has grown from

A noninvasive isotopic approach to estimate the bone lead contribution to blood in children: Implications for assessing the efficacy of lead abatement

3.5 billion in 1996 to

Prevention of childhood lead poisoning.

28.6 billion in 2010, according to the Organic Trade Association. Organic products are now sold in specialty stores and conventional supermarkets. Organic products contain numerous marketing claims and terms, only some of which are standardized and regulated. In terms of health advantages, organic diets have been convincingly demonstrated to expose consumers to fewer pesticides associated with human disease. Organic farming has been demonstrated to have less environmental impact than conventional approaches. However, current evidence does not support any meaningful nutritional benefits or deficits from eating organic compared with conventionally grown foods, and there are no well-powered human studies that directly demonstrate health benefits or disease protection as a result of consuming an organic diet. Studies also have not demonstrated any detrimental or disease-promoting effects from an organic diet. Although organic foods regularly command a significant price premium, well-designed farming studies demonstrate that costs can be competitive and yields comparable to those of conventional farming techniques. Pediatricians should incorporate this evidence when discussing the health and environmental impact of organic foods and organic farming while continuing to encourage all patients and their families to attain optimal nutrition and dietary variety consistent with the US Department of Agriculture’s MyPlate recommendations. This clinical report reviews the health and environmental issues related to organic food production and consumption. It defines the term “organic,” reviews organic food-labeling standards, describes organic and conventional farming practices, and explores the cost and environmental implications of organic production techniques. It examines the evidence available on nutritional quality and production contaminants in conventionally produced and organic foods. Finally, this report provides guidance for pediatricians to assist them in advising their patients regarding organic and conventionally produced food choices.

Iodine Deficiency, Pollutant Chemicals, and the Thyroid: New Information on an Old Problem

Lead hazard control measures to reduce children’s exposure to household lead sources often result in only limited reductions in blood lead levels. This may be due to incomplete remediation of lead sources and/or to the remobilization of lead stores from bone, which may act as an endogenous lead source that buffers reductions in blood lead levels. Here we present a noninvasive isotopic approach to estimate the magnitude of the bone lead contribution to blood in children following household lead remediation. In this approach, lead isotopic ratios of a child’s blood and 5-day fecal samples are determined before and after a household intervention aimed at reducing the child’s lead intake. The bone lead contribution to blood is estimated from a system of mass balance equations of lead concentrations and isotopic compositions in blood at the different times of sample collection. The utility of this method is illustrated with three cases of children with blood lead levels in the range of 18–29 μg/dL. In all three cases, the release of lead from bone supported a substantial fraction of the measured blood lead level postintervention, up to 96% in one case. In general, the lead isotopic compositions of feces matched or were within the range of the lead isotopic compositions of the household dusts with lead loadings exceeding U.S. Environmental Protection Agency action levels. This isotopic agreement underscores the utility of lead isotopic measurements of feces to identify household sources of lead exposure. Results from this limited number of cases support the hypothesis that the release of bone lead into blood may substantially buffer the decrease in blood lead levels expected from the reduction in lead intake.

Project TENDR: Targeting Environmental Neuro-Developmental Risks The TENDR Consensus Statement.

Although past national public health efforts have reduced lead exposure significantly, lead poisoning remains the most common environmental health problem affecting American children. Currently, lead exposure occurs predominantly through ingestion of lead-contaminated household dust and soil in older housing containing lead-based paint; exposure can be increased with housing deterioration or renovation. Environmental prevention efforts focus on improvement in risk assessment, development of housing-based standards for lead-based paint hazards, and safe and cost-effective lead hazard remediation techniques. Educational efforts address parental awareness of lead exposure pathways, hygiene, and housekeeping measures to prevent ingestion of dust and soil. Blood lead screening is recommended either universally at ages 1 and 2 years or in a targeted manner where local health departments can document a low prevalence of elevated blood lead levels. Nutritional interventions involve provision of regular meals containing adequate amounts of calcium and iron and supplementation for iron deficiency. Lead chelation should complement environmental, nutritional, and educational interventions, when indicated. Collaboration of multiple federal agencies in a new strategy to eliminate childhood lead poisoning should further prevention efforts.

Effect of a follow-up professional home cleaning on serial dust and blood lead levels of urban children

Many women of reproductive age in the United States are marginally iodine deficient, perhaps because the salt in processed foods is not iodized. Iodine deficiency, per se, can interfere with normal brain development in their offspring; in addition, it increases vulnerability to the effects of certain environmental pollutants, such as nitrate, thiocyanate, and perchlorate. Although pregnant and lactating women should take a supplement containing adequate iodide, only about 15% do so. Such supplements, however, may not contain enough iodide and may not be labeled accurately. The American Thyroid Association recommends that pregnant and lactating women take a supplement with adequate iodide. The American Academy of Pediatrics recommends that pregnant and lactating women also avoid exposure to excess nitrate, which would usually occur from contaminated well water, and thiocyanate, which is in cigarette smoke. Perchlorate is currently a candidate for regulation as a water pollutant. The Environmental Protection Agency should proceed with appropriate regulation, and the Food and Drug Administration should address the mislabeling of the iodine content of prenatal/lactation supplements.

Targeting Environmental Neurodevelopmental Risks to Protect Children

Summary: Children in America today are at an unacceptably high risk of developing neurodevelopmental disorders that affect the brain and nervous system including autism, attention deficit hyperactivity disorder, intellectual disabilities, and other learning and behavioral disabilities. These are complex disorders with multiple causes—genetic, social, and environmental. The contribution of toxic chemicals to these disorders can be prevented. Approach: Leading scientific and medical experts, along with children’s health advocates, came together in 2015 under the auspices of Project TENDR: Targeting Environmental Neuro-Developmental Risks to issue a call to action to reduce widespread exposures to chemicals that interfere with fetal and children’s brain development. Based on the available scientific evidence, the TENDR authors have identified prime examples of toxic chemicals and pollutants that increase children’s risks for neurodevelopmental disorders. These include chemicals that are used extensively in consumer products and that have become widespread in the environment. Some are chemicals to which children and pregnant women are regularly exposed, and they are detected in the bodies of virtually all Americans in national surveys conducted by the U.S. Centers for Disease Control and Prevention. The vast majority of chemicals in industrial and consumer products undergo almost no testing for developmental neurotoxicity or other health effects. Conclusion: Based on these findings, we assert that the current system in the United States for evaluating scientific evidence and making health-based decisions about environmental chemicals is fundamentally broken. To help reduce the unacceptably high prevalence of neurodevelopmental disorders in our children, we must eliminate or significantly reduce exposures to chemicals that contribute to these conditions. We must adopt a new framework for assessing chemicals that have the potential to disrupt brain development and prevent the use of those that may pose a risk. This consensus statement lays the foundation for developing recommendations to monitor, assess, and reduce exposures to neurotoxic chemicals. These measures are urgently needed if we are to protect healthy brain development so that current and future generations can reach their fullest potential.

Prevalence and Impact of Exposure to Interpersonal Violence Among Suburban and Urban Middle School Students

Children residing in Philadelphia, Pennsylvania, who were enrolled in a clinical trial oral chelation therapy (n = 73) were studied to determine the effects of a follow-up professional lead dust cleaning of their homes 18 mo after an initial cleaning and commencement of therapy. Home dust lead levels were determined from dust-wipe specimens collected from the kitchen and playroom floors, and from a playroom windowsill, prior to, immediately following, and 3 and 6 mo after the second cleaning. Childrens blood lead levels were assessed at 3-mo intervals before and after the follow-up cleaning. Professional cleaning produced immediate decreases in dust lead levels; however, dust lead re-accumulated to precleaning levels within 3-6 mo. Frequent, repeated cleanings may be required if blood lead or dust lead levels are to be reduced and sustained at low levels in urban homes.

A Comparison of Elevated Blood Lead Levels Among Children Living in Foster Care, Their Siblings, and the General Population

* Abbreviations: AAP — : American Academy of Pediatrics ADHD — : attention-deficit/hyperactivity disorder EPA — : Environmental Protection Agency PBDE — : polybrominated diphenyl ether TENDR — : Targeting Environmental Neuro-Developmental Risks Pregnant women, infants, and children are continually exposed to chemicals that are toxic to brain development. Yet too little has been done to protect them from the possibility of harm. In 2015, a diverse group of physicians and other health professionals, scientists, and advocates established Project Targeting Environmental Neuro-Developmental Risks (TENDR) to focus awareness and advocate for action against toxic chemicals that contribute to the risk of development of brain-based disorders in children, including intellectual and learning disabilities, autism, and attention-deficit/hyperactivity disorder (ADHD).1 Ten years ago, this landmark agreement among leading scientists and health professionals would not have been possible, but the accumulated evidence, which illustrates a pattern of toxicity, is credible and convincing. The release of the TENDR consensus statement coincided with the recent signing into law of the Frank R. Lautenberg Chemical Safety for the 21st Century Act. This act is the first update of the Toxic Substances Control Act since the law was adopted in 1976. This legislative effort was an important step toward protecting children from toxic chemicals, but, by itself, provides too little action at too slow a pace. Specific information is given below on how health care providers can respond to this legislation and advocate for safe policies that protect children. Additional information is also provided on advice providers can give to families regarding avoidance of toxic chemicals. The etiology of neurodevelopmental disorders is complex and multifactorial, but epidemiologic data, along with laboratory studies of animals, clearly indicate that exposures to certain toxic chemicals, even at very … Address correspondence to Deborah Hirtz, MD, FAAN, Department of Pediatrics and Neurology, HSRF 426, 149 Beaumont Ave, Burlington, VT 05405. E-mail: deborah.hirtz{at}uvmhealth.org