Cross-Sectional and Prospective Associations of Early Childhood Circulating Metals with Early and Mid-Childhood Cognition in the Project Viva

Details

• Personal Author:
  Bellinger D ; Cardenas A ; Landero J ; Lin P-ID ; Oken E ; Rifas-Shiman SL ; Thilakaratne R ; Wright RO
• Description:
  Background: Relatively little is known about the immediate and prospective neurodevelopmental impacts of joint exposure to multiple metals (i.e., metal mixtures) in early childhood. Objectives: To estimate associations of early childhood (approx. 3 years of age) blood metal concentrations with cognitive test scores at early and mid-childhood (approx. 8 years of age). Methods: We studied children from the Project Viva cohort. We measured erythrocyte concentrations of seven essential (Co, Cu, Mg, Mn, Mo, Se, and Zn) and eight non-essential metals (As, Ba, Cd, Cs, Hg, Pb, Sn, and Sr) in early childhood blood samples. Trained research assistants administered cognitive tests assessing vocabulary, visual-motor ability, memory, and general intelligence (standard deviations: approx. 10 points), in early and mid-childhood. We employed multivariable linear regression to examine associations of individual metals with test scores adjusting for confounders, other concurrently measured metals, and first-trimester maternal blood metals. We also estimated joint associations and explored interaction between metals in mixture analyses. Results: We analyzed 349 children (median whole blood Pb approx. 1 µg/dL). In cross-sectional analyses, each doubling of Pb was associated with lower visual-motor function (mean difference: -2.43 points, 95% confidence interval (CI): -4.01, -0.86) and receptive vocabulary, i.e., words understood (-1.45 points, 95% CI: -3.26, 0.36). Associations of Pb with mid-childhood cognition were weaker and less precise by comparison. Mg was positively associated with cognition in cross-sectional but not prospective analyses, and cross-sectional associations were attenuated in a sensitivity analysis removing adjustment for concurrent metals. We did not observe joint associations nor interactions. Discussion: In this cohort with low blood Pb levels, increased blood Pb was robustly associated with lower cognitive ability in cross-sectional analyses, even after adjustment for prenatal Pb exposure, and regardless of adjustment for metal co-exposures. However, associations with mid-childhood cognition were attenuated and imprecise, suggesting some buffering of Pb neurotoxicity in early life. What this study adds: Relatively few studies have comprehensively separated the effects of neurotoxic metals such as lead (Pb) from pre- and postnatal co-occurring metals, nor examined persistence of associations across childhood. In a cohort of middle-class children, we found higher early childhood (approx. 3 y) blood Pb was associated with lower scores on cognitive tests, independent of other metals and prenatal blood Pb. However, early childhood Pb was only weakly associated with cognition in mid-childhood (approx. 8 y). Our results suggest the effects of low-level Pb exposure may attenuate over time in some populations, implying the presence of factors that may buffer Pb neurotoxicity in early life. [Description provided by NIOSH]
• Subjects:
  Cohort Studies Metals Nervous System Occupational Health Safety
• Keywords:
  Children Cognitive Function Cohort Studies Cross Sectional Studies Neurotoxicity
• ISSN:
  0013-9351
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; Massachusetts ; New York ; OSHA Region 1 ; OSHA Region 2 ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  246
• NIOSHTIC Number:
  nn:20069395
• Citation:
  Environ Res 2024 Apr; 246:118068
• Contact Point Address:
  Andres Cardenas, Department of Epidemiology and Population Health, Stanford University, Stanford, CA, 94305
• Email:
  andres.cardenas@stanford.edu
• Federal Fiscal Year:
  2024
• Performing Organization:
  University of California, Berkeley
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Environmental Research
• End Date:
  20250630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:c067d643e4259edab864cc65ac9abacb0e1e2fdae32b5e72e094b65c68b3a86bf50389f490d379e35fc47f08d6d8fb7610b2ab88913ed52ac1e1445b11041d5d
• Download URL:
  https://stacks.cdc.gov/view/cdc/207882/cdc_207882_DS1.pdf
• File Type:
  [PDF - 3.81 MB ]