Exposition aux organochlorés et démence dans la population âgée du Canada

Authors: Medehouenou, Thierry Comlan Marc
Advisor: Laurin, DanielleAyotte, Pierre
Abstract: Few studies have investigated relationships between exposure to organochlorines (OCs) [polychlorinated biphenyls (PCBs) and organochlorine pesticides], which are persistent and neurotoxic environmental contaminants, and the risk for dementia or Alzheimer’s disease (AD), the most frequent type of dementia. The first objective of this thesis was to describe the OC concentrations in plasma of Canadians aged 65 and over, and to identify associated factors. The second objective was to evaluate the association between these concentrations and the prevalence of dementia and AD. The third objective was to evaluate the association between these concentrations and the incidence of dementia and AD. Analyses were performed using data from the Canadian Study of Health and Aging. Reported plasma lipid-weight PCB 105, 118, 138, 153, 156, 163, 170, 180, 183, and 187 and OC pesticide and their metabolite [β-hexachlorocyclohexane (β-HCH), hexachlorobenzene (HCB), oxychlordane, cis-nonachlor, trans-nonachlor, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p, p'-DDT), and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p, p'-DDE)] concentrations are similar to those from other older populations; age and sex were the main determinants of these concentrations. After adjustment for several conventional risk factors or confounders, PCB concentrations were not associated with the prevalence of dementia and AD. Except for HCB, cis-nonachlor and p, p'-DDT, no other pesticide or metabolite was associated with the prevalence of dementia and AD. Elevations of HCB, cis-nonachlor and p, p'-DDT concentrations were significantly associated with a reduced prevalence of dementia; only those of HCB were significantly associated with a reduced prevalence of AD. After a mean follow-up of five years, OC concentrations were not associated with the incidence of dementia and AD. However, additional analysis showed that elevations of PCB 153, 156 and 163 concentrations were associated with lower dementia-related cognitive performances. Overall, the results of the present thesis suggest that PCBs and OC pesticides and their metabolites were not related to clinically diagnosed dementia, in particular AD.
Document Type: Thèse de doctorat
Issue Date: 2013
Open Access Date: 19 April 2018
Permalink: http://hdl.handle.net/20.500.11794/24540
Grantor: Université Laval
Collection:Thèses et mémoires

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