Plasma polychlorinated biphenyl and organochlorine pesticide concentrations in dementia: the Canadian Study of Health and Aging.
BACKGROUND
Even though polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides are recognized as neurotoxicants, few studies have investigated their associations with dementia. Here, we assess associations of plasma PCB and OC pesticide concentrations with all-cause dementia and Alzheimer's disease (AD).


METHODS
Analyses are based on data from the Canadian Study of Health and Aging, a population-based study of men and women aged 65+ years at baseline. PCB and OC pesticide concentrations were measured in 2023 participants who had complete clinical evaluations and blood samples; 574 had dementia, including 399 cases of AD. Concentrations were log-transformed and used as continuous variables in logistic regression models to assess their individual associations with dementia and AD.


RESULTS
After adjustment for blood collection period, total plasma lipids, age, sex, education, apolipoprotein E e4 allele (ApoE4), tobacco and alcohol use, rural/urban residence, and comorbidities, elevated plasma PCB concentrations were not associated with increased prevalence of dementia and AD. Elevated concentrations of some OC pesticides and metabolites such as hexachlorobenzene, cis-nonachlor and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane were significantly associated with a reduced prevalence of dementia. A significant reduced prevalence of AD was also observed with elevated hexachlorobenzene concentrations. Other OC pesticides and metabolites were not associated with the prevalence of dementia or AD. No effect modification by sex and ApoE4 was observed for either dementia or AD.


CONCLUSIONS
Elevated plasma PCB and OC pesticide concentrations were not associated with higher prevalence of all-cause dementia and AD. The possibility of modest reductions in prevalence with specific OC pesticides remains to be further investigated given the cross-sectional design of this study.
Faculté de pharmacie, Université Laval, Quebec City, Québec, Canada; Centre d'excellence sur le vieillissement de Québec, Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Quebec City, Québec, Canada.
Thierry Comlan Marc
TC
Medehouenou
Faculté de médecine, Département de médecine sociale et préventive, Université Laval, Quebec City, Québec, Canada; Axe Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Quebec City, Québec, Canada; Laboratoire de toxicologie, Institut national de santé publique du Québec, Quebec City, Québec, Canada.
Pierre
P
Ayotte
Centre d'excellence sur le vieillissement de Québec, Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Quebec City, Québec, Canada.
Pierre-Hugues
PH
Carmichael
Faculté de pharmacie, Université Laval, Quebec City, Québec, Canada; Centre d'excellence sur le vieillissement de Québec, Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Quebec City, Québec, Canada.
Edeltraut
E
Kröger
Centre d'excellence sur le vieillissement de Québec, Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Quebec City, Québec, Canada; Faculté de médecine, Département de médecine sociale et préventive, Université Laval, Quebec City, Québec, Canada.
René
R
Verreault
Faculté de médecine, Département de médecine sociale et préventive, Université Laval, Quebec City, Québec, Canada; Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
Joan
J
Lindsay
Faculté de médecine, Département de médecine sociale et préventive, Université Laval, Quebec City, Québec, Canada; Axe Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Quebec City, Québec, Canada; Laboratoire de toxicologie, Institut national de santé publique du Québec, Quebec City, Québec, Canada.
Éric
É
Dewailly
School of Public Health and Health Systems, University of Waterloo, Waterloo, Ontario, Canada; Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada.
Suzanne L
SL
Tyas
Faculté de médecine, Département de médecine sociale et préventive, Université Laval, Quebec City, Québec, Canada; Centre de recherche de l'Institut universitaire en santé mentale de Québec, Quebec City, Québec, Canada.
Alexandre
A
Bureau
Faculté de pharmacie, Université Laval, Quebec City, Québec, Canada; Centre d'excellence sur le vieillissement de Québec, Santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Quebec City, Québec, Canada. Electronic address: Danielle.Laurin@pha.ulaval.ca.
Danielle
D
Laurin
D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003704:Dementia / Q000097:blood* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000097:blood*; D016015:Logistic Models; D008297:Male; D010575:Pesticides / Q000097:blood*; D011078:Polychlorinated Biphenyls / Q000097:blood*; D015995:Prevalence
D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D011078:Polychlorinated Biphenyls
Alzheimer disease; Dementia; Exposure; Organochlorine pesticide; Polychlorinated biphenyl