Factors associated with risk of transition to high likelihood of dementia profile in population‐based surveys of aging: a longitudinal analysis

Abstract

AbstractBackgroundDementia (Major Neurocognitive Disorder) is associated with acquired cognitive impairment and functional decline in daily life. Several population‐based surveys of aging similar to the American Health and Retirement Study exist worldwide. In these studies, cognitive performance and functional status are available, but not the diagnosis of dementia. We previously identified participants with high likelihood of dementia using cross‐sectional data from these studies and unsupervised machine‐learning (Cleret de Langavant et al., 2018; 2020). Here, we propose an application of this method by assessing simultaneously six waves, i.e., minimum 11‐year follow‐up for each participant, in order to study factors associated with risk of transition toward dementia.MethodWe used a modified version of a previously developed unsupervised machine‐learning algorithm in the Survey of Health, Ageing and Retirement in Europe (SHARE). We restrained the analysis to participants with available data at each wave (N = 5,536, 9 countries). Cognitive tests and autonomy variables were used to discriminate three groups: one healthy ageing group (Healthy), one characterised by mobility but no functional impairment (Mobility), and one with probable dementia (Dementia). We examined the role of several factors in transitioning from one group to another one using multi‐state models with age as time‐scale.ResultsHazard ratios (HR) examination confirmed that higher education lowers the risk of transition to mobility impairment and to dementia (HRhealthy→mobility = 0.46 [0.42 ‐ 0.50], HRmobility→dementia = 0.44 [0.32 ‐ 0.62], and HRhealthy→dementia = 0.58 [0.36 ‐ 0.92]). Similarly, obesity, stroke, hypertension, and poor hearing were significant risk factors. Isolation and depression were found to increase the risk of transition from Mobility to Dementia group (HRmobility→dementia = 2.97 [2.08 ‐ 4.24] & HRmobility→dementia = 2.23 [1.86 ‐ 2.67], respectively) and from Healthy to Dementia group (HRhealthy→dementia = 5.56 [2.39 ‐ 12.94]) & HRhealthy→dementia = 1.98 [1.33 ‐ 2.95], respectively). Results for smoking and alcohol were inconclusive.ConclusionWhile obesity, stroke, hypertension, poor hearing, depression and isolation were associated with an increased risk of transition to the Dementia group, high educational attainment was protective.