title: Perfluoroalkyl substances, thyroid hormones, and neuropsychological status in older adults.
abstract: Minimal data exist regarding the neurotoxicity of perfluoroalkyl substances (PFASs) in aging populations and the possible mediating effects of thyroid hormones (THs). Hence, the aims of this study were to: (i) assess associations between PFASs and neuropsychological function, and (ii) determine if such associations are mediated by changes in circulating THs in an aging population. We measured perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), total thyroxine (T4) and free thyroxine (fT4) in serum and performed neuropsychological tests in 126 men and women aged 55-74 years and living in upper Hudson River communities. Multivariable linear regressions were conducted to assess associations between PFASs and neuropsychological test scores. Mediation analyses were performed in a subset of 87 participants for whom information was available on both PFASs and THs. We calculated TH-mediated, non-TH mediated, and total effects of PFASs on neuropsychological test scores. Higher PFOA was associated with better performance in tasks of the California Verbal Learning Test and the Wisconsin Card Sorting Test. Higher PFOS was associated with improved performance in a Wechsler Memory Scale subtest and Block Design Subtest (BDT) total scores. There was no evidence of mediation by THs for PFOA-neuropsychological function associations. However, T4 and fT4 partially mediated the protective effect of PFOS on BDT total scores. Our findings do not suggest that PFASs are associated with poor neuropsychological function. There was some evidence of mediation for the association between PFASs and neuropsychological functions by THs, although some other modes of action also appear likely.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States.
authors.forename: Srishti
authors.initials: S
authors.lastname: Shrestha
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States; Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bloom
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States.
authors.forename: Recai
authors.initials: R
authors.lastname: Yucel
authors.affiliation: Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States; Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Empire State Plaza, P.O. Box 509, Albany, NY 12201, United States.
authors.forename: Richard F
authors.initials: RF
authors.lastname: Seegal
authors.affiliation: Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Empire State Plaza, P.O. Box 509, Albany, NY 12201, United States; Department of Biomedical Sciences, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States.
authors.forename: Robert
authors.initials: R
authors.lastname: Rej
authors.affiliation: Department of Psychology, University at Albany, State University of New York, Albany, NY, 12222, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McCaffrey
authors.affiliation: Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Empire State Plaza, P.O. Box 509, Albany, NY 12201, United States.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States; Division of Environmental Health Sciences, Wadsworth Center, New York State Department of Health, Empire State Plaza, P.O. Box 509, Albany, NY 12201, United States.
authors.forename: Kurunthachalam
authors.initials: K
authors.lastname: Kannan
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States; Department of Environmental Health Sciences, School of Public Health, University at Albany, State University of New York, One University Place, Rensselaer, NY 12144, United States. Electronic address: efitzgerald@albany.edu.
authors.forename: Edward F
authors.initials: EF
authors.lastname: Fitzgerald
mesh_terms: D000368:Aged; D017738:Alkanesulfonic Acids / Q000097:blood*; D001288:Attention; D002210:Caprylates / Q000097:blood*; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000097:blood*; D056344:Executive Function; D005260:Female; D005466:Fluorocarbons / Q000097:blood*; D006801:Humans; D007858:Learning; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011930:Reaction Time; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*
chemical_list: D017738:Alkanesulfonic Acids; D002210:Caprylates; D004785:Environmental Pollutants; D005466:Fluorocarbons; D013972:Thyrotropin; C023036:perfluorooctanoic acid; C076994:perfluorooctane sulfonic acid; D013974:Thyroxine
keywords: Neuropsychological status; Older adults; Perfluoroalkyl substances; Thyroid hormones