Blood Lead Levels and Learning Disabilities: A Cross-Sectional Study of the 2003–2004 National Health and Nutrition Examination Survey (NHANES)

Abstract

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 2003–2004 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 µg 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) = 1.03–1.43). The relationship remained significant when examining covariates such as gender and race (OR = 1.19, 95% CI = 1.00–1.40). 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 = 0.56–1.056), a non-plausibly biologically related outcome of blood Pb levels. Persons in the 50th–75th (12.80%) and 75th–100th (17.14%) percentiles of blood Pb were significantly more likely to have LDs than persons in the 0–50th 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.

The legacy lead deposition in soils and its impact on cognitive function in preschool-aged children in the United States

“…It adds to the literature on the cognitive development (Sánchez (2017), Chen (2016), Fiorini and Keane (2014), Autor et al (2014), Spears (2012)) by looking at the effect of an overlooked environmental factor: exposure to lead in topsoil. Our results strengthen the associational evidence on the neurodevelopmental effects of lead exposure in children (Lanphear et al 2005, NTP 2012, AAP 2016, Geier et al 2017, Delgado et al 2018, Lee et al 2018, and provides further evidence that those detrimental effects on cognitive function are causal (Rau et al 2015, Sauve-Syed 2017, Aizer et al 2018, Billings and Schnepel 2018, Gronqvist et al 2018. Its main finding is concerning: it indicates that lead may continue to impair cognition today, both in the United States and in other countries that have significant amounts of lead in topsoil (Chen et al 2015, Tóth et al 2016.…”

The Legacy Lead Deposition in Soils and Its Impact on Cognitive Function in Preschool-Aged Children in the United States

“…It adds to the literature on the cognitive development (Sánchez (2017), Chen (2016), Fiorini and Keane (2014), Autor et al (2014), Spears (2012)) by looking at the effect of an overlooked environmental factor: exposure to lead in topsoil. Our results strengthen the associational evidence on the neurodevelopmental effects of lead exposure in children (Lanphear et al 2005, NTP 2012, AAP 2016, Geier et al 2017, Delgado et al 2018, Lee et al 2018, and provides further evidence that those detrimental effects on cognitive function are causal (Rau et al 2015, Sauve-Syed 2017, Aizer et al 2018, Billings and Schnepel 2018, Gronqvist et al 2018. Its main finding is concerning: it indicates that lead may continue to impair cognition today, both in the United States and in other countries that have significant amounts of lead in topsoil (Chen et al 2015, Tóth et al 2016.…”

Study protocol to examine the relationship between environmental exposure to lead and blood lead levels among children from day-care centres in Ekurhuleni Metropolitan Municipality

“…9 Exposure to lead on a daily basis in young children can lead to the development of learning difficulties, short concentration span, emotional problems, antisocial behaviour, poor academic performance and neurodevelopmental deficits. [10][11][12][13][14][15] These conditions, especially neurodevelopmental effects, may cause exposed children to engage in delinquent behaviour, aggression, violent behaviour or criminal behaviour in their later years. [16][17][18][19] Studies conducted in high-income countries show that children from these countries have lower BLLs when compared with LMICs.…”