TY - JOUR
T1 - Exposure to polychlorinated biphenyls and organochlorine pesticides and risk of dementia, Alzheimer's disease and cognitive decline in an older population
T2 - A prospective analysis from the Canadian Study of Health and Aging
AU - Medehouenou, Thierry Comlan Marc
AU - Ayotte, Pierre
AU - Carmichael, Pierre Hugues
AU - Kröger, Edeltraut
AU - Verreault, René
AU - Lindsay, Joan
AU - Dewailly, Éric
AU - Tyas, Suzanne L.
AU - Bureau, Alexandre
AU - Laurin, Danielle
N1 - Funding Information:
The core funding for phases 1 and 2 of the Canadian Study of Health and Aging was provided by the Seniors’ Independence Research Program, through the Health Canada’s National Health Research and Development Program (NHRDP). Other funding was provided by Pfizer Canada Incorporated, by Bayer Incorporated and by the British Columbia Health Research Foundation. The core funding for phase 3 was provided by the Canadian Institutes of Health Research (CIHR). Other funding was provided by Merck-Frosst and Janssen-Ortho. The present study was financially supported by grants from the CIHR. Dr. Medehouenou was recipient of a PhD scholarship from the Alzheimer Society of Canada (ASC) and the Canadian Dementia Knowledge Translation Network (CDKTN). Drs. Bureau and Laurin were supported by scientist awards from the Fonds de Recherche du Québec – Santé (FRQS). All these sources of funding have no role in the design of this study and collection, analysis, and interpretation of data and in writing the manuscript.
Publisher Copyright:
© 2019 The Author(s).
PY - 2019/6/14
Y1 - 2019/6/14
N2 - 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.
AB - 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.
KW - Alzheimer's disease
KW - Cognitive decline
KW - Dementia
KW - Organochlorine pesticide
KW - Polychlorinated biphenyl
UR - http://www.scopus.com/inward/record.url?scp=85067296869&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85067296869&partnerID=8YFLogxK
U2 - 10.1186/s12940-019-0494-2
DO - 10.1186/s12940-019-0494-2
M3 - Article
C2 - 31200706
AN - SCOPUS:85067296869
SN - 1476-069X
VL - 18
JO - Environmental Health: A Global Access Science Source
JF - Environmental Health: A Global Access Science Source
IS - 1
M1 - 57
ER -