{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T20:05:05Z","timestamp":1779912305316,"version":"3.53.1"},"reference-count":23,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2017,10,10]],"date-time":"2017-10-10T00:00:00Z","timestamp":1507593600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"CoMeD, Inc."},{"name":"Institute of Chronic Illnesses, Inc."}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>Difficulties in the acquisition and use of listening, speaking, reading, writing, reasoning or mathematical abilities are present among persons diagnosed with learning disabilities (LDs). Previous studies suggest a significant relationship between lead (Pb) exposure and LDs. This study evaluated the potential dose-response relationship between blood Pb levels and the risk of LDs. This cross-sectional study examined 1411 children (32,788,743 weighted-persons) between 6 and 15 years old from the 2003\u20132004 National Health and Nutrition Examination Survey (NHANES) by analyzing demographics, health related-questions, and laboratory tests using survey logistic and frequency modeling in SAS. On a \u00b5g Pb\/dL basis, a significant dose-dependent relationship between increasing blood Pb levels and increasing risk of LDs was observed (odds ratio (OR) = 1.21, 95% confidence interval (CI) = 1.03\u20131.43). The relationship remained significant when examining covariates such as gender and race (OR = 1.19, 95% CI = 1.00\u20131.40). By contrast, no dose-dependence was observed between increasing blood Pb levels and the risk of hay fever in the last year (OR = 0.77, 95% CI = 0.56\u20131.056), a non-plausibly biologically related outcome of blood Pb levels. Persons in the 50th\u201375th (12.80%) and 75th\u2013100th (17.14%) percentiles of blood Pb were significantly more likely to have LDs than persons in the 0\u201350th percentile of blood Pb (8.78%). An estimated 1 million persons born in the US from 1989 to 1998 developed LDs from elevated blood Pb levels. Overall, this study revealed a significant dose-dependent association between increasing childhood blood Pb levels and the risk of a LD diagnosis, but it was not possible to ascribe a direct cause-effect relationship between blood Pb exposure and LD diagnosis. Childhood Pb exposure should be considered when evaluating children with LDs, and continuing efforts should be made to reduce Pb exposure.<\/jats:p>","DOI":"10.3390\/ijerph14101202","type":"journal-article","created":{"date-parts":[[2017,10,10]],"date-time":"2017-10-10T10:34:29Z","timestamp":1507631669000},"page":"1202","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":40,"title":["Blood Lead Levels and Learning Disabilities: A Cross-Sectional Study of the 2003\u20132004 National Health and Nutrition Examination Survey (NHANES)"],"prefix":"10.3390","volume":"14","author":[{"given":"David","family":"Geier","sequence":"first","affiliation":[{"name":"Institute of Chronic Illnesses, Inc., 14 Redgate Ct, Silver Spring, MD 20905, USA"},{"name":"CoMeD, Inc., Silver Spring, MD 20905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Janet","family":"Kern","sequence":"additional","affiliation":[{"name":"Institute of Chronic Illnesses, Inc., 14 Redgate Ct, Silver Spring, MD 20905, USA"},{"name":"CoMeD, Inc., Silver Spring, MD 20905, USA"},{"name":"CONEM US Autism Research Group, Allen, TX 75013, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark","family":"Geier","sequence":"additional","affiliation":[{"name":"Institute of Chronic Illnesses, Inc., 14 Redgate Ct, Silver Spring, MD 20905, USA"},{"name":"CoMeD, Inc., Silver Spring, MD 20905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2017,10,10]]},"reference":[{"key":"ref_1","unstructured":"Agency for Toxic Substances & Disease Registry (2017, September 28). 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