Date of Award

January 2012

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Kathleen M. McCarty

Second Advisor

Amalia Laborde

Abstract

Background

Lead has long been established as a potent neurotoxin, childhood being a key period of exposure due to rapid development at that stage in life. While lead is known to cause harmful health effects in the entire population, it is known to particularly damage the developing nervous system in children and potentially interfere with behavioral development. In 2001 a small cohort of children were identified with elevated blood lead level in Montevideo, Uruguay.

Objectives

This study investigated whether 2001 blood lead levels (BLL's) or current (2011) BLL's have had an effect on the behavioral outcomes in this group of adolescents.

Methods

A cohort study of 60 adolescents (mean age 15.2 years) from Montevideo was identified in 2001. Children with elevated BLL's in 2001 (mean 2001 BLL= 13.2 μg/dL, SD= 5.2) were re-identified and tested for current (2011) BLL's (mean 2011 BLL= 4.2 μg/dL, SD= 2.7) using atomic absorption spectrometry. The Child Behavior Checklist, a standardized assessment of behavioral problems, was administered to the adolescents. Linear regression was used to assess the relationship between 2001 BLL's, current BLL's, and the behavioral outcomes.

Results

2001 BLL's were found to be significantly associated with total problem behavioral score (β=0.98, 95% CI= 0.12-1.85) as well as the social (β=0.80, 95% CI= 0.20-1.40) and externalizing (β=0.93, 95% CI= 0.08-1.78) problem subscales when controlling for current (2011) BLL's and age. 2011 BLL's were not found to be significantly associated with behavioral outcomes. Additionally, 2011 BLL's were found to be significantly lower than 2001 BLL's (Wilcoxon paired test p= 1.90E-8).

Conclusion

This study confirms evidence that increased childhood exposure to lead is associated with subsequent negative behavioral outcomes, and suggests that childhood lead exposure has a stronger impact on behavioral outcomes than current exposure levels. Additionally, BLL's have been significantly reduced since 2001 in this population.

Comments

This is an Open Access Thesis.

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