Cognitive maintenance in older adults in social classes: a secondary analysis of the longitudinal SHARE data.

Background: Cognitive maintenance-defined as a capacity to maintain good or excellent cognitive functioning-is a valuable ageing outcome. Socio-demographic, dementia risk and protective factors may contribute differently to it across social classes. However, these effects have not been adequately assessed yet.

Objective: This study aims to evaluate the effects of socio-demographic, risks and protective factors on the probability of cognitive maintenance in older adults stratified by social classes.

Methods: Participants aged 65-85 years at the baseline from the Survey on Health, Ageing and Retirement in Europe (Waves 5 (2013) and 7 (2017)) were included. Cognitive maintenance was operationalised as six or more words recalled on the 10-word delayed recall test at baseline and follow-up. Dementia-specific risks and protective factors were selected from global strategies for dementia prevention. Multilevel logistic regressions with the country of residence as a random-effect variable were constructed to compare the relative effect of contributors across social classes.

Results: 20 960 participants from 14 countries were included in the analysis. The pseudo-R² was 0.24, 0.28, 0.41 and 0.32 in participants of higher, middle, lower and not known social classes. Age, number of leisure activities and country of residence were significant predictors for all social classes. Effects of gender, depression, obesity, frailty, alcohol, education, occupation and personality traits vary across social classes.

Conclusion: Studying contributors to cognitive maintenance separately in social classes may show possible targets of public health strategies for improving cognitive health in populations and reducing social inequalities in cognitive health.