Aims

Up to 25% of the global burden of disease is estimated to stem from preventable environmental exposures. Starting in utero, millions of children worldwide are exposed to toxic chemicals, including the metals lead, cadmium, and mercury, from natural and anthropogenic sources. Research clearly demonstrates that individually these toxic metals contribute to neurobehavioral deficits in children. It is also accepted that simultaneous exposure to multiple metals is the norm rather than an anomaly. Yet, surprisingly little is known about the combined effects of early exposure to multiple metals on child development and behaviour. Important research gaps, hinder our ability to set policies, create prevention or intervention measures, and care for affected individuals. First, except for select or specific population groups, the exposure to metals in the general population is likely to be of low magnitude. The patterns of exposure in the general population need to be established. Second, it is important to understand what sociodemographic factors are likely to predict exposures so that risk factors can be appropriately described and communicated. Most importantly, there is little understanding of the extent to which metals interact to produce deficits. Thus, the consequences, both in the short and the long-term, of multiple metal exposures need to be determined. The aim of this study is to 1) model the patterns of in utero exposure to three toxic metals (lead, cadmium and mercury), 2) compare sociodemographic factors/variables among groups of women with lowest and highest exposure patterns to identify salient predictors of exposure, and 3) examine the neurobehavioural consequences of exposure for the women's offspring using measures of early temperament and neurocognitive development.

Hypotheses

The central hypothesis is that women falling into the highest metal exposure pattern will have children with more difficult temperaments and lower developmental scores than women falling into the lowest exposure pattern.