Wisconsin Longitudinal Study (WLS), the Initial Lifetime’s Impact on Alzheimer’s Disease (WLS‐ILIAD): A Novel Opportunity to Study the Influence of Education on ADRD

Abstract

AbstractBackgroundThe importance of education in shaping brain health and dementia risk are increasingly supported, although the mechanisms by which these life course factors impact late life cognition remain elusive due to a scarcity of full life‐course longitudinal studies. A new data collection wave of the Wisconsin Longitudinal Study (WLS), the Initial Lifetime’s Impact on Alzheimer’s Disease (WLS‐ILIAD), stands to address this gap. The WLS cohort is a randomly selected community sample that’s been followed since 1957, offering a wealth of prospectively collected lifespan data to pull from. Now that this cohort has reached their 80’s, the ILIAD study aims to detect dementia prevalence in this sample, and when combined with prior data waves, offers an unparalleled opportunity to explore how full life‐course and sociodemographic factors shape the relationship between education and dementia risk and resilience.MethodWLS‐ILIAD employs a multi‐phasic study design. In Phase 1, the modified Telephone Interview for Cognitive Status (TICS‐m) was administered to all eligible participants to screen for dementia risk. Those performing below cutoff (TICS‐m≤28) were selected for Phase 2 to complete more robust cognitive assessment and to obtain comprehensive health history. Cognitive diagnoses were determined by multidisciplinary consensus panel. Proxy assessments were employed for participants who were deceased or unable to complete the assessment.ResultPreliminary results indicate a response rate of ∼78%. Approximately 4,800 participants completed Phase 1, with 1,227 (26%) falling below cutoff for dementia risk (TICS‐m≤28). Of those completing Phase 2, 460 participants were classified as normal cognition, 443 mild cognitive impairment (MCI), and 197 dementia. Another 300 dementia cases were identified via proxy. Participants diagnosed with MCI or dementia tended to be older, ApoeE‐4 allele carriers, and had a lower high school IQ. Of those diagnosed with dementia, 88% reported no prior clinical workup or existing cognitive diagnosis.ConclusionResults of the WLS‐ILIAD study yields detailed cognitive diagnostic classifications for this sample. When combined with prospectively collected life course data, the WLS cohort offers a unique opportunity to explore the impact of education on risk and resilience factors for dementia outcomes, leading to important public policy and public health implications.