Follow-Up of Children Overexposed to Lead

Abstract

The purpose of this study is to assess the nature and magnitude of the deleterious health effects of subclinical over-exposure to lead in children. The study stems from concerns about the impact on the health of children in city slums who ingest leaded paint without overt evidence of poisoning and the health implication of rising levels of lead in the environment from automotive emissions. The study sample was derived mainly from a registry of children on whom blood lead determinations had been made by the New York City Department of Health and was supplemented by siblings of the registry cases and children from a lead belt area who had extractions of deciduous teeth in dental clinics. Information was obtained through parental interview, medical records, and psy-chometric evaluation. The data show that deleterious health effects occur in children who were treated for severe lead poisoning and in children without diagnosed lead poisoning who had elevated blood leads (>0.06 mg-%). In the absence of diagnosed lead poisoning or elevated blood leads, excess lead exposure, measured in terms of high levels of lead in teeth, was not associated with deleterious health effects.

Raised Lead Levels and Impaired Cogn Itive/Behavioural Functioning: A Review of the Evidence

“…However, the findings are weakly consistent with the view that blood lead levels above 50 are associated with very slight intellectual decrements. Albert et al (1974) conducted a threeto 1 1-year follow-up study of New York children who had had blood lead estimations carried out because of suspected lead exposure. Groups were compared according to whether there was encephalopathy, whether there were other symptoms, whether the blood lead exceeded 60pg/100ml, and (among those with blood lead levels below 60) whether there were high or low levels of dentine lead (cut-off point not given but the means were 58 and 12 respectively).…”

Efeitos de metais pesados sobre o controle central do equilíbrio hidroeletrolítico.

“…Utilizando rotas de penetração similares, o cádmio também atinge o sistema nervoso central causando disfunções bastante evidentes, tanto em animais de laboratório quanto em seres humanos (HASTINGS et al., 1978). A intoxicação crônica por chumbo em humanos pode levar a disfunções do sistema nervoso central caracterizadas como hiperatividade idiopática (DAVID, 1974), redução de QI (ALBERT et al, 1974), assim como dificuldades auditivas, diminuição da atenção e problemas relacionados à linguagem (LANSDOWN et al, 1983) e ao aprendizado (NORDBERG, 1984). Do ponto de vista neuroquímico, a presença de chumbo no cérebro perturba a função de vários neurotransmissores, como a serotonina (WIDMER et al, 1991), a dopamina (SHAFIQ, 1991), o GABA (SHAILESH; DESIRAJU, 1990), a noradrenalina (WIDMER et al, 1991) e a acetilcolina (SHIH; HANIN, 1978).…”