title: Beneficial effect of bilingualism on Alzheimer's disease CSF biomarkers and cognition.
abstract: Bilingualism as a component of cognitive reserve has been claimed to delay the onset of Alzheimer's disease (AD). However, its effect on cerebrospinal fluid (CSF) AD-biomarkers has not been investigated. We assessed cognitive performance and CSF AD-biomarkers, and potential moderation effect of bilingualism on the association between age, CSF AD-biomarkers, and cognition. Cognitively healthy middle-aged participants classified as monolinguals (n = 100, nCSF= 59), early (n = 81, nCSF= 55) and late bilinguals (n = 97, nCSF= 52) were evaluated. Models adjusted for confounders showed that bilinguals performed better than monolinguals on digits backwards (early-bilinguals p = 0.003), Judgment of Line Orientation (JLO) (early-bilinguals p = 0.018; late-bilinguals p = 0.004), and Trail Making Test-B (late-bilinguals p = 0.047). Early bilingualism was associated with lower CSF total-tau (p = 0.019) and lower prevalence of preclinical AD (NIA-AA classification) (p = 0.02). Bilingualism showed a moderation effect on the relationship between age and CSF AD-biomarkers and the relationship between age and executive function. We conclude that bilingualism contributes to cognitive reserve enhancing executive and visual-spatial functions. For the first time, this study reveals that early bilingualism is associated with more favorable CSF AD-biomarker profile.
authors.affiliation: Department of Neurology, CITA-Alzheimer Foundation, San Sebastian, Spain.
authors.forename: Ainara
authors.initials: A
authors.lastname: Estanga
authors.affiliation: Department of Neurology, CITA-Alzheimer Foundation, San Sebastian, Spain.
authors.forename: Mirian
authors.initials: M
authors.lastname: Ecay-Torres
authors.affiliation: Department of Neurology, CITA-Alzheimer Foundation, San Sebastian, Spain.
authors.forename: Almudena
authors.initials: A
authors.lastname: Ibañez
authors.affiliation: Department of Neurology, CITA-Alzheimer Foundation, San Sebastian, Spain.
authors.forename: Andrea
authors.initials: A
authors.lastname: Izagirre
authors.affiliation: Department of Neuroimaging, CITA-Alzheimer Foundation, San Sebastian, Spain; Donostia Unit, Osatek SA, Donostia University Hospital, San Sebastian, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Villanua
authors.affiliation: Department of Neuroimaging, CITA-Alzheimer Foundation, San Sebastian, Spain.
authors.forename: Maite
authors.initials: M
authors.lastname: Garcia-Sebastian
authors.affiliation: Clinical Epidemiology Unit, Donostia University Hospital, Biodonostia, CIBER-ESP, San Sebastian, Spain.
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Iglesias Gaspar
authors.affiliation: Department of Neurology, CITA-Alzheimer Foundation, San Sebastian, Spain.
authors.forename: Ane
authors.initials: A
authors.lastname: Otaegui-Arrazola
authors.affiliation: Department of Neurology, CITA-Alzheimer Foundation, San Sebastian, Spain.
authors.forename: Ane
authors.initials: A
authors.lastname: Iriondo
authors.affiliation: Department of Neurology, CITA-Alzheimer Foundation, San Sebastian, Spain.
authors.forename: Monserrat
authors.initials: M
authors.lastname: Clerigue
authors.affiliation: Department of Neurology, CITA-Alzheimer Foundation, San Sebastian, Spain. Electronic address: pmlage@cita-alzheimer.org.
authors.forename: Pablo
authors.initials: P
authors.lastname: Martinez-Lage
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000523:psychology*; D015415:Biomarkers / Q000134:cerebrospinal fluid; D003071:Cognition; D000066492:Cognitive Aging / Q000523:psychology*; D058245:Cognitive Reserve / Q000502:physiology*; D015331:Cohort Studies; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019303:Multilingualism; D009483:Neuropsychological Tests; D065855:Spatial Processing; D016875:tau Proteins / Q000134:cerebrospinal fluid*
chemical_list: D015415:Biomarkers; D016875:tau Proteins
keywords: Bilingualism; CSF biomarkers; Cognitive performance; Cognitive/brain reserve; Cohort studies; Preclinical Alzheimer's disease