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Geochemical Risk Factors for Mental Functioning, Based on the Ontario Longitudinal Study of Aging (LSA) IV. The Role of Silicon-Containing Compounds

Published online by Cambridge University Press:  29 November 2010

W. F. Forbes ,
N. Agwani  and
P. Lachmaniuk
W. F. Forbes
Affiliation:
University of Waterloo and Water Resources Branch, Ministry of the Environment and Energy
N. Agwani
Affiliation:
University of Waterloo and Water Resources Branch, Ministry of the Environment and Energy
P. Lachmaniuk
Affiliation:
University of Waterloo and Water Resources Branch, Ministry of the Environment and Energy
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Abstract

Following previous studies on the associations between aluminium (Al) water concentrations and relatively high risks of a measure of mental impairment, the role of silica (SiO2) as a possible confounding variable is investigated. The bivariate associations show that the lowest odds, representing an approximation of relative risks, are observed at “mild” SiO2 concentrations. Multivariate analyses indicate that, if interaction terms are included, the odds comparing higher and lower SiO2 concentrations are different than if an interaction term is not included. There are also indications that at relatively high Al levels, high SiO2 concentrations lower the odds, consistent with previous suggestions by Birchall. The implication is that when investigating the role of Al in the etiology of various measures of mental impairment, it is important to consider the effects of other water constituents, and also the different chemical forms of Al present in treated water. The desirability of additional work is stressed, preferably using more definitive outcomes than indications of mental impairment.

Résumé

On examine le rôle de la silice (SiO2) comme variable de confusion potentielle sur la base d'études menées sur les associations entre les concentrations d'aluminium (Al) dans l'eau et les risques relativement élevés de la déficience intellectuelle. Les associations bivariées montrent que les probabilités les plus faibles, qui sont une approximation des risques relatifs, sont caractéristiques des concentrations «moyennes» de SiO2. Si on inclut les termes d'interaction, les analyses multivariées montrent que les ratios comparant les concentrations élevées et faibles de SiO2 seraient différents si le terme d'interaction était omis. On observe aussi, qu'à des niveaux relativement élevés d'aluminium, des concentrations de SiO2 élevées réduisent les probabilités, ce qui est conforme aux idées avancées par Birchall. On en déduit qu'il est important, dans l'étude du rôle de l'aluminium dans l'étiologie des diverses mesures de la déficience intellectuelle, de prendre en considération les effets des autres substances ainsi que les diverses formes chimiques de l'aluminium qui sont présentes dans l'eau traitée. On insiste sur la nécessité de poursuivre les travaux, en utilisant plus des indicateurs de résultats autres que la déficience intellectuelle.

Keywords

Mental ImpairmentAluminiumSilicaDéficit cognitifaluminiumsilice
Type
Articles
Information
Canadian Journal on Aging / La Revue canadienne du vieillissement , Volume 14 , Issue 4 , Winter/hiver 1995 , pp. 630 - 641
Copyright
Copyright © Canadian Association on Gerontology 1995

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References

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