{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T16:18:16Z","timestamp":1790266696969,"version":"4.1.0"},"reference-count":28,"publisher":"American Chemical Society (ACS)","issue":"5","license":[{"start":{"date-parts":[[2017,12,29]],"date-time":"2017-12-29T00:00:00Z","timestamp":1514505600000},"content-version":"vor","delay-in-days":4713,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2005,5,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Increases in peak blood lead concentrations, which occur at 18\u201330 months of age in the United States, are thought to result in lower IQ scores at 4\u20136 years of age, when IQ becomes stable and measurable. Data from a prospective study conducted in Boston suggested that blood lead concentrations at 2 years of age were more predictive of cognitive deficits in older children than were later blood lead concentrations or blood lead concentrations measured concurrently with IQ. Therefore, cross-sectional associations between blood lead and IQ in school-age children have been widely interpreted as the residual effects of higher blood lead concentrations at an earlier age or the tendency of less intelligent children to ingest more leaded dust or paint chips, rather than as a causal relationship in older children. Here we analyze data from a clinical trial in which children were treated for elevated blood lead concentrations (20\u201344 \u03bcg\/dL) at about 2 years of age and followed until 7 years of age with serial IQ tests and measurements of blood lead. We found that cross-sectional associations increased in strength as the children became older, whereas the relation between baseline blood lead and IQ attenuated. Peak blood lead level thus does not fully account for the observed association in older children between their lower blood lead concentrations and IQ. The effect of concurrent blood level on IQ may therefore be greater than currently believed.<\/jats:p>","DOI":"10.1289\/ehp.7625","type":"journal-article","created":{"date-parts":[[2005,2,2]],"date-time":"2005-02-02T16:22:25Z","timestamp":1107361345000},"page":"597-601","source":"Crossref","is-referenced-by-count":126,"title":["IQ and Blood Lead from 2 to 7 Years of Age: Are the Effects in Older Children the Residual of High Blood Lead Concentrations in 2-Year-Olds?"],"prefix":"10.1021","volume":"113","author":[{"given":"Aimin","family":"Chen","sequence":"first","affiliation":[{"name":"1Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kim N.","family":"Dietrich","sequence":"additional","affiliation":[{"name":"2Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio, USA;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James H.","family":"Ware","sequence":"additional","affiliation":[{"name":"3Harvard School of Public Health, Harvard University, Boston, Massachusetts, USA;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jerilynn","family":"Radcliffe","sequence":"additional","affiliation":[{"name":"4Department of Psychology, Children\u2019s Hospital of Philadelphia, and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Walter J.","family":"Rogan","sequence":"additional","affiliation":[{"name":"1Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA;"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2005,2,2]]},"reference":[{"key":"2026080607024229900_micit1","author":"Bayley"},{"key":"2026080607024229900_micit2","doi-asserted-by":"crossref","first-page":"855","DOI":"10.1542\/peds.90.6.855","article-title":"Low-level lead exposure, intelligence and academic achievement: a long-term follow-up study","volume":"90","author":"Bellinger","year":"1992","journal-title":"Pediatrics"},{"key":"2026080607024229900_micit3","doi-asserted-by":"crossref","first-page":"711","DOI":"10.1093\/aje\/154.8.711","article-title":"Stability and change in children\u2019s intelligence quotient scores: a comparison of two socioeconomically disparate communities","volume":"154","author":"Breslau","year":"2001","journal-title":"Am J Epidemiol"},{"key":"2026080607024229900_micit4","author":"Caldwell"},{"key":"2026080607024229900_micit5","doi-asserted-by":"crossref","first-page":"1517","DOI":"10.1056\/NEJMoa022848","article-title":"Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter","volume":"348","author":"Canfield","year":"2003","journal-title":"N Engl J Med"},{"key":"2026080607024229900_micit6","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1016\/0892-0362(94)00086-S","article-title":"A higher level of analysis: Bellinger\u2019s, interpreting the literature on lead and child development","volume":"17","author":"Dietrich","year":"1995","journal-title":"Neurotoxicol Teratol"},{"key":"2026080607024229900_micit7","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/0892-0362(93)90043-N","article-title":"The developmental consequences of low to moderate prenatal and postnatal lead exposure: intellectual attainment in the Cincinnati Lead Study Cohort following school entry","volume":"15","author":"Dietrich","year":"1993","journal-title":"Neurotoxicol Teratol"},{"key":"2026080607024229900_micit8","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1542\/peds.114.1.19","article-title":"Effect of chelation therapy on the neuropsychological and behavioral development of lead-exposed children after school entry","volume":"114","author":"Dietrich","year":"2004","journal-title":"Pediatrics"},{"key":"2026080607024229900_micit9","doi-asserted-by":"crossref","first-page":"827","DOI":"10.1001\/jama.1993.03510070049021","article-title":"Declining blood lead levels and cognitive change in children","volume":"270","author":"Ernhart","year":"1993","journal-title":"JAMA"},{"key":"2026080607024229900_micit10","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1093\/phr\/115.6.521","article-title":"Cognitive deficits associated with blood lead concentrations &lt; 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