Gail A. Wasserman

Low-Level Environmental Lead Exposure and Children's Intellectual Function: An International Pooled Analysis

Lead is a confirmed neurotoxin, but questions remain about lead-associated intellectual deficits at blood lead levels < 10 μg/dL and whether lower exposures are, for a given change in exposure, associated with greater deficits. The objective of this study was to examine the association of intelligence test scores and blood lead concentration, especially for children who had maximal measured blood lead levels < 10 μg/dL. We examined data collected from 1,333 children who participated in seven international population-based longitudinal cohort studies, followed from birth or infancy until 5–10 years of age. The full-scale IQ score was the primary outcome measure. The geometric mean blood lead concentration of the children peaked at 17.8 μg/dL and declined to 9.4 μg/dL by 5–7 years of age; 244 (18%) children had a maximal blood lead concentration < 10 μg/dL, and 103 (8%) had a maximal blood lead concentration < 7.5 μg/dL. After adjustment for covariates, we found an inverse relationship between blood lead concentration and IQ score. Using a log-linear model, we found a 6.9 IQ point decrement [95% confidence interval (CI), 4.2–9.4] associated with an increase in concurrent blood lead levels from 2.4 to 30 μg/dL. The estimated IQ point decrements associated with an increase in blood lead from 2.4 to 10 μg/dL, 10 to 20 μg/dL, and 20 to 30 μg/dL were 3.9 (95% CI, 2.4–5.3), 1.9 (95% CI, 1.2–2.6), and 1.1 (95% CI, 0.7–1.5), respectively. For a given increase in blood lead, the lead-associated intellectual decrement for children with a maximal blood lead level < 7.5 μg/dL was significantly greater than that observed for those with a maximal blood lead level ≥7.5 μg/dL (p = 0.015). We conclude that environmental lead exposure in children who have maximal blood lead levels < 7.5 μg/dL is associated with intellectual deficits.

Child development: risk factors for adverse outcomes in developing countries

Poverty and associated health, nutrition, and social factors prevent at least 200 million children in developing countries from attaining their developmental potential. We review the evidence linking compromised development with modifiable biological and psychosocial risks encountered by children from birth to 5 years of age. We identify four key risk factors where the need for intervention is urgent: stunting, inadequate cognitive stimulation, iodine deficiency, and iron deficiency anaemia. The evidence is also sufficient to warrant interventions for malaria, intrauterine growth restriction, maternal depression, exposure to violence, and exposure to heavy metals. We discuss the research needed to clarify the effect of other potential risk factors on child development. The prevalence of the risk factors and their effect on development and human potential are substantial. Furthermore, risks often occur together or cumulatively, with concomitant increased adverse effects on the development of the worlds poorest children.

Water Manganese Exposure and Children's Intellectual Function in Araihazar, Bangladesh

Exposure to manganese via inhalation has long been known to elicit neurotoxicity in adults, but little is known about possible consequences of exposure via drinking water. In this study, we report results of a cross-sectional investigation of intellectual function in 142 10-year-old children in Araihazar, Bangladesh, who had been consuming tube-well water with an average concentration of 793 μg Mn/L and 3 μg arsenic/L. Children and mothers came to our field clinic, where children received a medical examination in which weight, height, and head circumference were measured. Children’s intellectual function was assessed on tests drawn from the Wechsler Intelligence Scale for Children, version III, by summing weighted items across domains to create Verbal, Performance, and Full-Scale raw scores. Children provided urine specimens for measuring urinary As and creatinine and were asked to provide blood samples for measuring blood lead, As, Mn, and hemoglobin concentrations. After adjustment for sociodemographic covariates, water Mn was associated with reduced Full-Scale, Performance, and Verbal raw scores, in a dose–response fashion; the low level of As in water had no effect. In the United States, roughly 6% of domestic household wells have Mn concentrations that exceed 300 μg Mn/L, the current U.S. Environmental Protection Agency lifetime health advisory level. We conclude that in both Bangladesh and the United States, some children are at risk for Mn-induced neurotoxicity.

The Voice DISC-IV With Incarcerated Male Youths: Prevalence of Disorder

OBJECTIVES (1) To accurately assess rate of psychiatric disorder in incarcerated juveniles, and (2) to examine the feasibility of using a self-administered, comprehensive structured psychiatric assessment with those youths. METHOD In 1999-2000, 292 recently admitted males in secure placement with New Jersey and Illinois juvenile justice authorities provided self-assessments by means of the Voice Diagnostic Interview Schedule for Children-IV, a comprehensive, computerized diagnostic instrument that presents questions via headphones. RESULTS Assessments were well tolerated by youths, staff, and parents; 92% of approached youths agreed. Rates of disorder were comparable to prior diagnostic assessment studies with interviewers. Beyond expectable high rates of disruptive and substance use disorders, youths reported high levels of anxiety and mood disorders, with over 3% reporting a past-month suicide attempt. Youths with substance use disorder were significantly more likely to be incarcerated for substance offenses than were youths with no disorder or those with other, non-substance use disorders. CONCLUSIONS Although the study identified rates of disorder generally comparable to those of prior investigations, some differences, understandable in the context of measurement variations, are apparent. Those variations offer recommendations for mental health assessment practices for youths in the justice system that would include using a comprehensive self-report instrument, pooling across parent and youth informants for certain disorders, focusing on current disorder, and flexibility regarding consideration of impairment.

Water arsenic exposure and intellectual function in 6-year-old children in Araihazar, Bangladesh.

Background We recently reported results of a cross-sectional investigation of intellectual function in 10-year-olds in Bangladesh, who had been exposed to arsenic from drinking water in their home wells. Objectives We present results of a similar investigation of 301 randomly selected 6-year-olds whose parents participated in our ongoing prospective study of the health effects of As exposure in 12,000 residents of Araihazar, Bangladesh. Methods Water As and manganese concentrations of tube wells at each home were obtained by surveying all study region wells. Children and mothers were first visited at home, where the quality of home stimulation was measured, and then seen in our field clinic, where children received a medical examination wherein weight, height, and head circumference were assessed. We assessed children’s intellectual function using subtests drawn from the Wechsler Preschool and Primary Scale of Intelligence, version III, by summing weighted items across domains to create Verbal, Performance, Processing Speed, and Full-Scale raw scores. Children provided urine specimens for measuring urinary As and were asked to provide blood samples for blood lead measurements. Results Exposure to As from drinking water was associated with reduced intellectual function before and after adjusting for water Mn, for blood lead levels, and for sociodemographic features known to contribute to intellectual function. With covariate adjustment, water As remained significantly negatively associated with both Performance and Processing Speed raw scores; associations were less strong than in our previously studied 10-year-olds. Conclusion This second cross-sectional study of As exposure expands our concerns about As neurotoxicity to a younger age group.

Arsenic and manganese exposure and children's intellectual function

Recently, epidemiologic studies of developmental neurotoxicology have been challenged to increase focus on co-exposure to multiple toxicants. Earlier reports, including our own work in Bangladesh, have demonstrated independent associations between neurobehavioral function and exposure to both arsenic (As) and manganese (Mn) in school-aged children. Our earlier studies, however, were not designed to examine possible interactive effects of exposure to both As and Mn. To allow investigation of possible synergistic impact of simultaneous exposures, we recruited a new sample of 299 8-11 year old children, stratified by design on As (above and below 10 μg/L) and Mn (above and below 500 μg/L) concentrations of household wells. When adjusted only for each other, both As and Mn in whole blood (BAs; BMn) were significantly negatively related to most WISC-IV subscale scores. With further adjustment for socio-demographic features and ferritin, BMn remained significantly associated with reduced Perceptual Reasoning and Working Memory scores; associations for BAs, and for other subscales, were expectably negative, significantly for Verbal Comprehension. Urinary As (per gram creatinine) was significantly negatively associated with Verbal Comprehension scores, even with adjustment for BMn and other contributors. Mn by As interactions were not significant in adjusted or unadjusted models (all ps>0.25). Findings are consistent with other reports documenting adverse impact of both As and Mn exposure on child developmental outcomes, although associations appear muted at these relatively low exposure levels.

Parenting Predictors of Early Conduct Problems in Urban, High-Risk Boys

OBJECTIVE As part of a larger, prospective study, the authors examined concurrent and prospective relations among parenting and child antisocial behavior in inner-city boys at high risk for delinquent behavior. METHOD One hundred twenty-six younger brothers (aged 6 to 10 years) of convicted delinquents in New York City and their parents were assessed; 15 months later 112 boys were reassessed. Demographics, parenting, and child diagnosis were examined as they relate to child externalizing behavior problems. Hierarchical multiple regression analyses predicted changes in Externalizing scores from year I parenting. RESULTS At years I and II, 22% and 27% of boys, respectively, scored above the clinical cutoff for Externalizing. Controlling for earlier Externalizing, each of three domains of parenting still made significant independent contributions to later Externalizing scores, explaining 17% of the variance. Altogether this model explained 51% of the variance in year II Externalizing scores. CONCLUSIONS Data support a cumulative risk model, whereby each of several adverse parenting factors further compounds the likelihood of child conduct problems.

Developmental and sex differences in types of conduct problems

Maternal report of types of conduct problems in a high-risk sample of 228 boys and 80 girls (ages 4–18) were examined, using a version of the Child Behavior Checklist, expanded to include a range of covert and overt antisocial items (stealing, lying, physical aggression, relational aggression, substance use, and impulsivity). Age and sex effects were investigated. Boys were significantly more physically aggressive than girls. There were no sex differences for stealing, lying, relational aggression, and substance use. Lying and substance use increased with age, whereas relational aggression and impulsivity peaked during early adolescence. A small group of girls had pervasive conduct problems across multiple domains. For some domains such as stealing, lying, and relational aggression, girls showed at least as many problems as boys. Girls, in general, tended to have fewer conduct problems. On the other hand, when assessed across multiple domains, conduct problems in high-risk girls were possibly more pervasive than in high-risk boys, suggesting the possibility of a gender paradox.

The Yugoslavia Prospective Lead Study: contributions of prenatal and postnatal lead exposure to early intelligence

To investigate associations between the timing of lead (Pb) exposure on early intelligence, we examined the results of psychometric evaluations at ages 3, 4, 5, and 7 years, from 442 children whose mothers were recruited during pregnancy from a smelter town and a non-lead-exposed town in Yugoslavia. We compared the relative contribution of prenatal blood lead (BPb) with that of relative increases in BPb in either the early (0-2 years) or the later (from 2 years on) postnatal period to child intelligence measured longitudinally at ages 3 and 4 (McCarthy GCI), 5 (Wechsler Preschool and Primary Scale of Intelligence-Revised, WPPSI-R IQ), and 7 (Wechsler Intelligence Scale for Children-version III, WISC-III IQ), controlling for: Home Observation for Measurement of the Environment (HOME) quality; maternal age, intelligence, education, and ethnicity; and birthweight and gender. Elevations in both prenatal and postnatal BPb were associated with small decrements in young childrens intelligence.

Mental health assessments in juvenile justice: report on the consensus conference.

OBJECTIVE At national, state, and local levels, there is increasing recognition of the importance of identifying and responding to the mental health needs of youths in the juvenile justice system, as policymakers and practitioners struggle to find ways to address causes and correlates of juvenile crime and delinquency. The proposed guidelines for mental health assessment provide explicit information about how, why, and when to obtain mental health information on justice youths at each important juncture in processing. METHOD A national group of expert researchers and practitioners convened in April 2002. Experts derived six recommendations, following the expert consensus method, for conducting mental health assessments in juvenile justice settings. Experts had broad experience creating collaborations between juvenile justice, mental health, and child welfare systems and understood the policy and health implications of conducting such assessments in juvenile justice settings. RESULTS Consensus Conference recommendations regarding screening for emergent risk, screening and assessment of mental health service needs, comprehensive mental health assessment components, assessment before community re-entry, need for periodic reassessment, and staff training are presented. CONCLUSION Deriving specific recommendations that can be implemented systematically is a necessary first step toward policy changes that will optimize the standard of care for this vulnerable population.