Grant: Operating Grant

A recent review of evidence from Canadian studies reveals accumulating evidence of learning disabilities and illness attributable to exposure to environmental contaminants (EC). It is, therefore, important to further elucidate the associations of EC with health and development. This requires the design and implementation of longitudinal cohorts of pregnant women and children with exposure assessments at critical windows and sensitive endpoints documented along the continuum of human development. Several effect studies of exposure to EC have been conducted, but follow-ups through adolescence are scarce. The Inuit from Arctic Quebec are among the populations most highly exposed to mercury, polychlorinated biphenyls and chlorinated pesticides due to frequent consumption of fish and marine mammals. We have recruited a pregnancy cohort in Arctic Quebec between 1993-96. Cord blood concentrations of EC were obtained, and the cohort was followed at 1-, 5- and 11-year of age. We are now proposing to follow up this cohort during the adolescent period to document the long-term effects of pre- and postnatal exposure to these contaminants. Outcomes of interests include cognitive, affective and behavioural development, physical growth, and metabolic precursors of obesity, diabetes and cardiovascular disease. The sample will consist of 200 adolescents aged 16 to 19 years. Each child will be evaluated during a 3-hr visit, and current exposure to EC will be assayed from blood samples. The proposed study is of public health importance in light of increasing Hg body burdens in the North due to increasing emissions in developing countries, challenging the health of the Inuit. Although exposure levels in Southern Canada are markedly lower than those found in Arctic Quebec, recent evidence from our studies of the Inuit population indicates adverse effects on development at levels of contaminant exposure commonly found in Southern Canadian populations.