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document
The Treatment of Lead-exposed Children ( TLC ) trial : design and recruitment for a study of the effect of oral chelation on growth and development in toddlers . Exposure to lead impairs cognitive development in young children , but the benefits of lowering blood lead pharmacologically are not clear . This report describes the design , recruitment , enrolment and baseline results of the Treatment of Lead-Exposed Children ( TLC ) trial , a randomised , multicentre , placebo-controlled , double-blind clinical trial of the effects of treating lead-exposed children with succimer , a drug that enhances urinary excretion of lead , on cognitive , behavioural and physical development . TLC clinical sites were in Baltimore , Cincinnati and Columbus , Newark and Philadelphia . Children were eligible for TLC if they were between 12 and 33 months of age , had a confirmed blood lead concentration between 20 and 44 micrograms/dL and lived in a residence suitable for lead dust reduction . Randomised children received up to three 26-day courses of succimer or placebo , and were then followed for 3 years . The study can detect a three-point difference in full-scale IQ at 3-year follow-up . Statistical power for the other end points is more difficult to estimate . A total of 1854 children were evaluated and 780 children were randomised between August 1994 and January 1997 . The mean age of randomised children was 24 months and mean blood lead level 26 micrograms/dL . Three-quarters were African-American . Most children had poor , single mothers who had completed 12 or fewer years of school and who lived in older , poorly maintained residences .
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Intervention_Pharmacological
oral chelation
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Intervention_Pharmacological
succimer
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Intervention_Pharmacological
succimer
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Intervention_Control
placebo
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Outcome_Mental
full-scale IQ
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Participant_Condition
Lead-exposed Children ( TLC )
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Participant_Condition
toddlers .