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Medehouenou TCM, Ayotte P, Carmichael PH, Kröger E, Verreault R, Lindsay J, Dewailly É, Tyas SL, Bureau A, Laurin D. Exposure to polychlorinated biphenyls and organochlorine pesticides and risk of dementia, Alzheimer's disease and cognitive decline in an older population: a prospective analysis from the Canadian Study of Health and Aging. Environ Health 2019; 18:57. [PMID: 31200706 PMCID: PMC6570931 DOI: 10.1186/s12940-019-0494-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 05/31/2019] [Indexed: 05/28/2023]
Abstract
BACKGROUND Little attention has been paid to neurotoxicants on the risk of dementia. Exposure to known neurotoxicants such as polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides is suspected to have adverse cognitive effects in older populations. OBJECTIVE To assess whether plasma concentrations of PCBs and OC pesticides are associated with the risk of cognitive decline, Alzheimer's disease (AD) and of all-cause dementia in the Canadian older population. METHODS Analyses were based on data from the Canadian Study of Health and Aging, a 3-phase, 10-year population-based study of individuals aged 65+ years. Analyses included 669 clinically assessed subjects, of which 156 developed dementia including 108 incident cases of AD. Subjects were screened at each phase with the 100-point Modified Mini-Mental State Examination (3MS), a measurement of global cognitive function. Statistical analyses included Cox proportional hazards model when the outcome was dementia or AD, and a repeated-measure mixed model when the outcome was the 3MS score. RESULTS No association of PCB and OC pesticides with the risk of dementia and AD was observed. Elevated concentrations of PCB congeners nos 118, 153, 156, 163, and OC pesticides 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and its metabolite 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) were significantly associated with cognitive decline as assessed with the 3MS. A posteriori analyses suggested that only p,p'-DDE was significantly related to a higher cognitive decline in time based on the 3MS among incident cases of dementia compared to subjects remaining nondemented. CONCLUSION PCB and OC pesticide plasma concentrations were not related to the incident diagnosis of neither dementia, nor AD. Using the 3MS scores as the outcome, higher concentrations of four PCB congeners and two OC pesticides were associated with lower cognitive performances in subjects. The association of p,p'-DDE with cognitive decline in time in incident cases of dementia merits further investigation.
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Affiliation(s)
- Thierry Comlan Marc Medehouenou
- Département de Génie d'imagerie médicale et de radiobiologie, École Polytechnique d'Abomey-Calavi, University of Abomey-Calavi, P.O. Box 2009, Cotonou, Abomey-Calavi, Republic of Benin.
- Centre d'excellence sur le vieillissement de Québec, CHU de Québec-Université Laval Research Center, and Centre de recherche sur les soins et les services de première ligne de l'Université Laval, Québec, Canada.
- Faculty of Pharmacy, Laval University, Québec, Canada.
| | - Pierre Ayotte
- Département de médecine sociale et préventive, Faculty of Medicine, Laval University, Québec, Canada
- Axe Santé des populations et pratiques optimales en santé, CHU de Québec-Université Laval Research Center, Québec, Canada
- Laboratoire de toxicologie, Institut national de santé publique du Québec, Québec, Canada
| | - Pierre-Hugues Carmichael
- Centre d'excellence sur le vieillissement de Québec, CHU de Québec-Université Laval Research Center, and Centre de recherche sur les soins et les services de première ligne de l'Université Laval, Québec, Canada
| | - Edeltraut Kröger
- Centre d'excellence sur le vieillissement de Québec, CHU de Québec-Université Laval Research Center, and Centre de recherche sur les soins et les services de première ligne de l'Université Laval, Québec, Canada
- Faculty of Pharmacy, Laval University, Québec, Canada
| | - René Verreault
- Centre d'excellence sur le vieillissement de Québec, CHU de Québec-Université Laval Research Center, and Centre de recherche sur les soins et les services de première ligne de l'Université Laval, Québec, Canada
- Département de médecine sociale et préventive, Faculty of Medicine, Laval University, Québec, Canada
- Axe Santé des populations et pratiques optimales en santé, CHU de Québec-Université Laval Research Center, Québec, Canada
- Institut sur le vieillissement et la participation sociale des aînés, Université Laval, Québec, Canada
| | - Joan Lindsay
- Département de médecine sociale et préventive, Faculty of Medicine, Laval University, Québec, Canada
- Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Éric Dewailly
- Département de médecine sociale et préventive, Faculty of Medicine, Laval University, Québec, Canada
- Axe Santé des populations et pratiques optimales en santé, CHU de Québec-Université Laval Research Center, Québec, Canada
- Laboratoire de toxicologie, Institut national de santé publique du Québec, Québec, Canada
| | - Suzanne L Tyas
- School of Public Health and Health Systems, and Department of Psychology, University of Waterloo, Waterloo, Canada
| | - Alexandre Bureau
- Département de médecine sociale et préventive, Faculty of Medicine, Laval University, Québec, Canada
- Centre de recherche de l'Institut universitaire en santé mentale de Québec, Québec, Canada
| | - Danielle Laurin
- Centre d'excellence sur le vieillissement de Québec, CHU de Québec-Université Laval Research Center, and Centre de recherche sur les soins et les services de première ligne de l'Université Laval, Québec, Canada
- Faculty of Pharmacy, Laval University, Québec, Canada
- Axe Santé des populations et pratiques optimales en santé, CHU de Québec-Université Laval Research Center, Québec, Canada
- Institut sur le vieillissement et la participation sociale des aînés, Université Laval, Québec, Canada
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