A comparison of elevated blood lead levels among children living in foster care, their siblings, and the general population

An Update on Childhood Lead Poisoning

Childhood lead poisoning is a multi-faceted, complex condition, which affects not only the child's health and well-being, but also the family's housing security, economic status, job security, and stress level. This review updates the emergency department clinician on the management of childhood lead poisoning. Infants and children are at higher risk than adults for lead exposure due to their smaller size and proportionately larger dose of ingested toxins, their proximity to ground dirt and indoor dust, their energy and curiosity, their oral exploratory and pica behaviors, their proportionately larger daily water and milk intake, and dietary preferences that differ markedly from those of adults. Pediatric health care providers working in the emergency department can provide medical management, as well as preventive counseling and guidance, to parents of children presenting with evidence of acute or chronic lead poisoning.

Strain specific effects of low level lead exposure on associative learning and memory in rats

Exposure to lead (Pb) remains a significant public health concern. Lead exposure in early life impairs the normal development of numerous cognitive and neurobehavioral processes. Previous work has shown that the effects of developmental Pb exposure on gene expression patterns in the brain are modulated by various factors including the developmental timing of the exposure, level of exposure, sex, and genetic background. Using gene microarray profiling, we previously reported a significant strain-specific effect of Pb exposure on the hippocampal transcriptome, with the greatest number of differentially expressed transcripts in Long Evans (LE) rats and the fewest in Sprague Dawley (SD) rats. The present study examined the extent to which this differential effect of Pb on hippocampal gene expression might influence behavior. Animals (males and females) were tested in a trace fear conditioning paradigm to evaluate effects of Pb exposures (perinatal (PERI; gestation to postnatal day 21) or early postnatal (EPN; postnatal day 1 to day 21)) on associative learning and memory. All animals (Pb-exposed and non-Pb-exposed controls) showed normal acquisition of the conditioned stimulus (tone)-unconditioned stimulus (footshock) association. Long Evans rats showed a significant deficit in short- and long-term recall, influenced by sex and the timing of Pb exposure (PERI or EPN). In contrast, Pb exposure had no significant effect on memory consolidation or recall in any SD rats. These results further demonstrate the important influence of genetic background to the functional outcomes from developmental Pb exposure.

Nutritional status of foster children in the U.S.: Implications for cognitive and behavioral development

OBJECTIVE

Children in foster care are at greater risk for poor health, physical, cognitive, behavioral, and developmental outcomes than are children in the general population. Considerable research links early nutrition to later cognitive and behavioral outcomes. The aim of this narrative review is to examine the prevalence of poor nutrition and its relation to subsequent health and development in foster children.

METHOD

Relevant studies for inclusion were identified from numerous sources (e.g., PubMed, Google Scholar, and reference sections). Inclusion criteria were studies published between 1990 and 2016 of (i) the nutritional status of children in foster care or (ii) the nutritional status of children exposed to early adversity (e.g., low-income and internationally adopted children) or (iii) the developmental effects of poor nutrition and micronutrient deficiencies.

RESULTS

Two key findings that have adverse implications for cognitive development emerged: (i) the prevalence of anemia and iron-deficiency anemia is higher among foster children than among the general population of children in the U.S., and (ii) the developmental demands of catch-up growth post-placement may lead to micronutrient deficiencies even after children have begun sufficient dietary intake of these nutrients. Moreover, there is a paucity of recent studies on the nutritional status of children in foster care, despite the multiple factors that may place them at risk for malnutrition.

CONCLUSION

Attention to nutritional status among care providers and medical professionals may remove one of the possible negative influences on foster children's development and in turn significantly alter their trajectories and place them on a more positive path early in life. Recommendations for further research, policy, and practice are discussed.

Medical Management and Trauma-Informed Care for Children in Foster Care

Children enter foster care with a myriad of exposures and experiences, which can threaten their physical and mental health and development. Expanding evidence and evolving guidelines have helped to shape the care of these children over the past two decades. These guidelines address initial health screening, comprehensive medical evaluations, and follow-up care. Information exchange, attention to exposures, and consideration of how the adversities, which lead to foster placement, can impact health is crucial. These children should be examined with a trauma lens, so that the child, caregiver, and community supports can be assisted to view their physical and behavioral health from the perspective of what we now understand about the impact of toxic stress. Health care providers can impact the health of foster children by screening for the negative health consequences of trauma, advocating for trauma-informed services, and providing trauma-informed anticipatory guidance to foster parents. By taking an organized and comprehensive approach, the health care provider can best attend to the needs of this vulnerable population.

Genetic diversity influences the response of the brain to developmental lead exposure

Although extrinsic factors, such as nutritional status, and some intrinsic genetic factors may modify susceptibility to developmental lead (Pb) poisoning, no studies have specifically examined the influence of genetic background on outcomes from Pb exposure. In this study, we used gene microarray profiling to identify Pb-responsive genes in rats of different genetic backgrounds, including inbred (Fischer 344 (F344)) and outbred (Long Evans (LE), Sprague Dawley (SD)) strains, to investigate the role that genetic variation may play in influencing outcomes from developmental Pb exposure. Male and female animals received either perinatal (gestation through lactation) or postnatal (birth through weaning) exposure to Pb in food (0, 250, or 750 ppm). RNA was extracted from the hippocampus at day 55 and hybridized to Affymetrix Rat Gene 1.0 ST Arrays. There were significant strain-specific effects of Pb on the hippocampal transcriptome with 978 transcripts differentially expressed in LE rats across all experimental groups, 269 transcripts differentially expressed in F344 rats, and only 179 transcripts differentially expressed in SD rats. These results were not due to strain-related differences in brain accumulation of Pb. Further, no genes were consistently differentially regulated in all experimental conditions. There was no set of "Pb toxicity" genes that are a molecular signature for Pb neurotoxicity that transcended sex, exposure condition, and strain. These results demonstrate the influence that strain and genetic background play in modifying the brain's response to developmental Pb exposure and may have relevance for better understanding the molecular underpinnings of the lack of a neurobehavioral signature in childhood Pb poisoning.

Emerging aspects of assessing lead poisoning in childhood

This review covers the epidemiology of lead poisoning in children on a global scale. Newer sources of lead poisoning are identified. The methods that are used to assess a population of children exposed to lead are discussed, together with the ways of undertaking an exposure risk assessment; this includes assessing the time course and identifying sources of lead exposure. Human assessment measures for lead toxicity, such as blood lead concentrations, deciduous tooth lead, and use of zinc protoporphyrin estimations are evaluated. The role of isotopic fingerprinting techniques for identifying environmental sources of exposure is discussed. Among emerging data on the cognitive and behavioral effects of lead on children, the review considers the growing evidence of neurocognitive dysfunction with blood lead concentrations even below 10 µg/dl. The challenge of assessing and explaining the risk that applies to an individual as opposed to a population is discussed. Intervention strategies to mitigate risk from lead are examined together with the limited role for and limitations of chelation therapy for lead. Lessons learned from managing a population lead-dust exposure event in Esperance, Western Australia in 2007 are discussed throughout the review.

Interventions to prevent child maltreatment and associated impairment

Although a broad range of programmes for prevention of child maltreatment exist, the effectiveness of most of the programmes is unknown. Two specific home-visiting programmes-the Nurse-Family Partnership (best evidence) and Early Start-have been shown to prevent child maltreatment and associated outcomes such as injuries. One population-level parenting programme has shown benefits, but requires further assessment and replication. Additional in-hospital and clinic strategies show promise in preventing physical abuse and neglect. However, whether school-based educational programmes prevent child sexual abuse is unknown, and there are currently no known approaches to prevent emotional abuse or exposure to intimate-partner violence. A specific parent-training programme has shown benefits in preventing recurrence of physical abuse; no intervention has yet been shown to be effective in preventing recurrence of neglect. A few interventions for neglected children and mother-child therapy for families with intimate-partner violence show promise in improving behavioural outcomes. Cognitive-behavioural therapy for sexually abused children with symptoms of post-traumatic stress shows the best evidence for reduction in mental-health conditions. For maltreated children, foster care placement can lead to benefits compared with young people who remain at home or those who reunify from foster care; enhanced foster care shows benefits for children. Future research should ensure that interventions are assessed in controlled trials, using actual outcomes of maltreatment and associated health measures.

Prenatal cocaine exposure: drug and environmental effects at 9 years

OBJECTIVE

To assess school-age cognitive and achievement outcomes in children with prenatal cocaine exposure, controlling for confounding drug and environmental factors.

STUDY DESIGN

At age 9 years, 371 children (192 cocaine exposure [CE]; 179 non-cocaine exposure [NCE]) were assessed for IQ and school achievement in a longitudinal, prospective study from birth. An extensive number of confounding variables were controlled, including quality of caregiving environment, polydrug exposure, blood lead level, iron-deficiency anemia (IDA), and foster/adoptive care.

RESULTS

Prenatal cocaine exposure predicted poorer perceptual reasoning IQ, with a linear relationship of the concentration of the cocaine metabolite benzoylecgonine to the degree of impairment. Effects were mediated through birth head circumference, indicating a relationship with fetal brain growth. Negative effects of alcohol, lead, and marijuana exposure and positive effects of the home environment were additive. The CE children in foster/adoptive care had better home environments and lower lead levels. School achievement was not affected.

CONCLUSIONS

Persistent teratologic effects of CE on specific cognitive functions and additive effects of alcohol, lead, and marijuana exposure; IDA; and the home environment were identified. Documenting environmental factors in behavioral teratology studies is important, because in this sample, CE was associated with better home environment and lower environmental risk in a substantial number of children.

Environmental lead toxicity and nutritional factors

Environmental lead toxicity is an old but persistent public health problem throughout the world and children are more susceptible to lead than adults because of their hand to mouth activity, increased respiratory rates and higher gastrointestinal absorption per unit body weight. In the last decade children's blood lead levels have fallen significantly in a number of countries. Despite this reduction, childhood lead toxicity continues to be a major public health problem for certain at-risk groups of children, and concern remains over the effects of lead on intellectual development. The currently approved clinical intervention method is to give chelating agents, which bind and removed lead from lead burdened tissues. Studies indicate, however, that there is a lack of safety and efficacy when conventional chelating agents are used. Several studies are underway to determine the beneficial effect of nutrients supplementation following exposure to lead. Data suggest that nutrients may play an important role in abating some toxic effects of lead. To explain the importance of using exogenous nutrients in treating environmental lead toxicity the following topics are addressed: (i) different sources of lead exposure/current blood lead levels and (ii) protective effects of nutrients supplementation (some essential elements and vitamins) in lead toxicity.

Recent developments in low-level lead exposure and intellectual impairment in children

In the last decade children's blood lead levels have fallen significantly in a number of countries, and current mean levels in developed countries are in the region of 3 Mu g/dL. Despite this reduction, childhood lead poisoning continues to be a major public health problem for certain at-risk groups of children, and concerns remain over the effects of lead on intellectual development in infants and children. The evidence for lowered cognitive ability in children exposed to lead has come largely from prospective epidemiologic studies. The current World Health Organization/Centers for Disease Control and Prevention blood level of concern reflects this and stands at 10 Mu g/dL. However, a recent study on a cohort of children whose lifetime peak blood levels were consistently less than 10 Mu g/dL has extended the association of blood lead and intellectual impairment to lower levels of lead exposure and suggests there is no safety margin at existing exposures. Because of the importance of this finding, we reviewed this study in detail along with other recent developments in the field of low-level lead exposure and children's cognitive development. We conclude that these findings are important scientifically, and efforts should continue to reduce childhood exposure. However, from a public health perspective, exposure to lead should be seen within the many other risk factors impacting on normal childhood development, in particular the influence of the learning environment itself. Current lead exposure accounts for a very small amount of variance in cognitive ability (1-4%), whereas social and parenting factors account for 40% or more.

[Children and adolescents in foster care: health problems and guidelines for their health care]

In Spain, between 8,000 and 10,000 children and adolescents enter foster or residential care every year. This article aims to provide a review to increase knowledge of the health problems of minors in foster care.Sixty-five percent of the studies consulted were performed in the USA, 25 % in Spain and 10 % in other developed and industrialized countries. These studies report that a high percentage of these minors present complicated and serious physical, mental, and/or developmental problems. However, no appreciable qualitative differences in the most frequent health problems presented by these minors have been observed and there is general consensus that the high-priority health needs are the provision of preventive and/or therapeutic psychopedagogic, psychiatric, dermatologic, dental, nutritional, ophthalmologic, respiratory and immunization services. Failure to identify and provide early treatment of the health needs of these minors not only adversely affects their quality of life and future physical, emotional and intellectual development, but can also increase their difficulties in adaptation while in foster care and their future social adaptation. Their permanent relationship with the biological or adoptive family when foster care stops could also be jeopardized. Therefore, all children and adolescents in foster care should receive initial health screenings, comprehensive assessments and monitoring of their physical, mental health, and developmental status. We provide guidelines for the healthcare of these minors, which should be of use to healthcare professionals taking care of these children and adolescents while they remain in foster care.