Assessing Dementia Prevalence in the Wisconsin Longitudinal Study: Cohort Profile, Protocol, and Preliminary Findings

Article type: Research Article

Authors: Williams, Victoria J.^{a; b; *} | Carlsson, Cynthia M.^{a; b; c} | Fischer, Anne^a | Johnson, Sterling C.^{a; b; c} | Lange, Kate^a | Partridge, Eileen^a | Roan, Carol^d | Asthana, Sanjay^{a; b; c; 1} | Herd, Pamela^{e; 1}

Affiliations: [a] Division of Geriatrics and Gerontology, Department of Medicine, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, WI, USA | [b] Wisconsin Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA | [c] Geriatric Research, Education, and Clinical Center (GRECC), William S. Middleton Memorial Veterans Hospital, Madison, WI, USA | [d] Department of Sociology, University of Wisconsin at Madison, Department of Sociology, Madison, WI, USA | [e] McCourt School of Public Policy, Georgetown University, Washington, DC, USA

Correspondence: [*] Correspondence to: Victoria J. Williams, PhD, Assistant Professor, University of Wisconsin –Madison, School of Medicine and Public Health, 3330 University Avenue, Suite 200, Madison, WI 53705, USA. Tel.: +1 608 265 3091; E-mail: vwilliams@medicine.wisc.edu.

Note: [1] Joint senior authors.

Abstract: Background:There is growing consensus that non-genetic determinants of dementia can be linked to various risk- and resiliency-enhancing factors accumulating throughout the lifespan, including socioeconomic conditions, early life experiences, educational attainment, lifestyle behaviors, and physical/mental health. Yet, the causal impact of these diverse factors on dementia risk remain poorly understood due to few longitudinal studies prospectively characterizing these influences across the lifespan. Objective:The Initial Lifespan’s Impact on Alzheimer’s Disease and Related Dementia (ILIAD) study aims to characterize dementia prevalence in the Wisconsin Longitudinal Study (WLS), a 60-year longitudinal study documenting life course trajectories of educational, family, occupational, psychological, cognitive, and health measures. Methods:Participants are surveyed using the modified Telephone Interview for Cognitive Status (TICS-m) to identify dementia risk. Those scoring below cutoff undergo home-based neuropsychological, physical/neurological, and functional assessments. Dementia diagnosis is determined by consensus panel and merged with existing WLS data for combined analysis. Results:Preliminary findings demonstrate the initial success of the ILIAD protocol in detecting dementia prevalence in the WLS. Increasing age, hearing issues, lower IQ, male sex, APOE4 positivity, and a steeper annualized rate of memory decline assessed in the prior two study waves, all increased likelihood of falling below the TICS-m cutoff for dementia risk. TICS-m scores significantly correlated with standard neuropsychological performance and functional outcomes. Conclusion:We provide an overview of the WLS study, describe existing key lifespan variables relevant to studies of dementia and cognitive aging, detail the current WLS-ILIAD study protocol, and provide a first glimpse of preliminary study findings.

Keywords: Alzheimer’s disease, dementia, epidemiologic determinants, health risk behaviors, prevalence

DOI: 10.3233/JAD-201422

Journal: Journal of Alzheimer's Disease, vol. 81, no. 2, pp. 751-768, 2021