Date of Award
May 2024
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Environmental Health Sciences
First Advisor
Amy Kalkbrenner
Committee Members
Amy Kalkbrenner, Robert Wright, Alexander Keil, Kurt Svoboda, Michael Laiosa
Keywords
Children, Cognition, Intellectual Functioning, Metals, Mexico, Mixtures
Abstract
Metals are part of the environmental exposures impacting children’s cognition, and they are studied traditionally in isolated scenarios of exposures in epidemiological studies. Historically, these exposures are assessed for human health effects with specific biomarkers, even in studies where additional information from different biomarkers is available, potentially allowing a loss of accuracy in exposure measurement. This dissertation seeks to examine the relationship between pre and postnatal metal exposures and children’s intellectual functioning in the Mexican context while including new methodological approaches to incorporate all the available biomarker information from a longitudinal birth cohort study. Chapter 1 included key concepts of metals focusing on epidemiological findings, as well as the relationship between these and children’s intellectual functioning. In addition, this chapter involves metal analysis in both single and mixture analysis as a background of epidemiological research on cognition, including the utilization of the last generation of epidemiological methods. Chapter 2 analyzes metals in the context of mixtures, allowing us to better analyze the co-pollutant confounding problem throughout the utilization of indexes. Here, we included nonessential (lead, cadmium, mercury, arsenic, strontium, barium, and cesium) and essential (manganese, copper, selenium, molybdenum, magnesium, and zinc) metals. Our results point out that co-pollutant confounding is a problem non-commonly analyzed when evaluating metals and children’s cognition, while in the Mexican context, there is a co-pollutant confounding problem where after adjusting by potential confounders and other metals, magnesium, molybdenum, zinc, and barium showed that the effect was masked by other metals. In addition, higher cadmium and arsenic levels showed the most negative effect on cognition, while those subjects with higher molybdenum and manganese levels showed the most positive effect. In this analysis, we did not find that the effect of metals on cognition varies by sex, nor does the effect of lead on cognition vary by other metals. Chapter 3 incorporates new causal inference approaches to evaluate the effect of hypothetical interventions to reduce the exposure, estimating the potential impact on children’s cognition. Here our results indicate that eliminating the domestic utilization of lead-glazed pottery during pregnancy and early childhood may improve children’s intellectual functioning. Chapter 4 is the analysis of our previous chapters with an emphasis on public health policies. My research highlights the necessity of better understanding the pattern and structure of our data when analyzing mixtures to have a real sense of the potential implications. Furthermore, my findings support the reduction of lead exposure and the positive impact of the potential interventions in the real world.
Recommended Citation
Florez Garcia, Victor Alfonso, "INVESTIGATING IMPACTS OF REAL-WORLD EXPOSURE MIXTURES OF TOXIC AND NUTRIENT METALS AND THE IMPACT OF REDUCING METALS IN GLAZED POTTERY IN MEXICO ON CHILD COGNITION" (2024). Theses and Dissertations. 3572.
https://dc.uwm.edu/etd/3572