Manganese Exposure and Intellectual and Executive Function Deficits in School-Aged Children from Montevideo, Uruguay

Objectives: To examine the association between low-level Mn exposure and cognitive performance in first-grade children. Methods: Children aged 6-8 years from Montevideo, Uruguay were enrolled from 11 schools (n=357). Children were evaluated with the Intra-Extra Dimensional Set Shift Test (IED) from the CANTAB battery and seven sub-tests from the Woodcock-Muñoz cognitive battery. An IQ score was derived. Hair manganese (HMn) concentrations (μg/g) were measured via IC-PMS and log2-transformed for statistical analysis. Water Mn (WMn) concentrations were measured via IC-PMS and log2-transformed for statistical analysis. Pre- and post-dimensional shift error and total error from the IED were dichotomized at the median. We examined the likelihood of having IED errors above the median for each doubling of HMn concentrations. We examined association between each doubling in HMn and performance on the Woodcock-Muñoz subtests and the estimated IQ score. Models were adjusted for sociodemographic (age, sex, HOME score, household density, maternal education, possessions score) and biological (blood lead level, hemoglobin) characteristics. Stratified analyses by iron status (as determined by hemoglobin level, dichotomized at the median), sex, and blood lead level (BLL) were performed. Results: HMn and WMn were 0.84, 0.1-25.7 μg/g and 1.6, 0.2-207.9 μg/dL, respectively. HMn and WMn were not correlated (r= -0.04), suggesting that water is not a source of Mn exposure. Each doubling in HMn was associated with lower scores on Visual-Auditory Learning (β [95%CI]: -1.8 [-3.0, -0.51]), Numbers Reversed (-4.8 [-7.6, -2.2]), Concept Formation (2.3 [-4.2, -0.33]), and Estimated IQ (-1.9 [-3.5, -0.37]). Significance of point estimates differed between boys and girls, among those > 3.80 μg/dL as compared to those < 3.80 μg/dL, and among children < 13.1 g/dL Hb as compared to children > 13.1 g/dL Hb but did not demonstrate evidence for effect medication as determined by overlap of confidence intervals.

Grantor dc:publisher

State University of New York at Buffalo

Year dc:date.issued

2018

Author dc:creator

• Smith, Tessa

Contributors dc:contributor

• Kordas, Katarzyna
• Epidemiology and Environmental Health

• epidemiology

Statement dc:rights

• Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.
• Copyright retained by author.

Language dc:language

eng

Handle dc:identifier

http://hdl.handle.net/10477/78047

OAI record oai:identifier

https://ubir.buffalo.edu/oai/request?verb=GetRecord&metadataPrefix=qdc&identifier=oai%3Aubir.buffalo.edu%3A10477%2F78047