Lead is a preventable environmental toxin that has been previously associated with deficits in cognition, academic performance, attention, and behavior in children. Very few studies, however, have examined the relationship between exposure to lead and documented developmental disabilities.
This study examined the relative risk of lead exposure on developmental disabilities in preschool-aged children.
A statewide lead surveillance data set containing blood lead level (BLL) was integrated with another statewide data set containing developmental disability classifications for special education placement for preschool-aged children.
The participants were the 85 178 children (average age 2.6 years) whose records in both data sets were able to be linked. Forty-six percent of the participants had an identified developmental disability.
Developmental disability classification served as the main outcome measure.
A high BLL, defined as 5 μg/dL or more, was associated with significantly increased risk for developmental disabilities (risk ratio [RR] = 1.04; 95% CI = 1.01-1.08), particularly intellectual disability (RR = 1.58, 95% CI = 1.10-2.25) and developmental delay (DD; RR = 1.11, 95% CI = 1.06-1.17).
The results of this study are consistent with previous research identifying an association between lead exposure and numerous intellectual and educational outcomes and demonstrate that high BLL is associated with meeting eligibility criteria for developmental disabilities in young children. Continued research, surveillance, and prevention efforts are needed to further reduce the negative impacts of lead on individuals and society. Reducing or eliminating lead exposure would improve outcomes for individual children (eg, better academic performance) and reduce the burden to society (eg, lower enrollments in special education systems).
Department of Psychology, University of Miami, Coral Gables, Florida (Drs Delgado, Ullery, and Scott); and Division of Community Health Promotion, Florida Department of Health, Tallahassee, Florida (Mss Jordan and Rajagopalan and Mr Duclos).
Correspondence: Christine F. Delgado, PhD, Department of Psychology, University of Miami, 5665 Ponce de Leon Blvd, Coral Gables, FL 33146 (firstname.lastname@example.org).
The contents of this work are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention. Data were provided by the Florida Department of Health, Bureau of Epidemiology Lead Poisoning Prevention Program and the Florida Department of Education, Bureau of Exceptional Education and Student Services. The authors also thank Antonio Gonzalez and Olga Camacho for their assistance in preparing the linked data set. This project was supported by Cooperative Agreement Number 5U38EH000941 from the Centers of Disease Control and Prevention.
The authors declare that they have no actual or potential competing financial interests.