Individual and environmental stressors in life course cognitive health disparities: Evidence from the Dutch Lifelines Cohort Study

We examine the age and socio-economic gradients in cognitive health and explore how both relate to environmental, health-behavioural, and psychosocial factors. We use data from the Lifelines Cohort Study, which includes two measures of cognitive health, as well as individual education, household income, and neighbourhood socio-economic status (NSES) scores as indicators of socio-economic position, comprising 109,669 individuals aged 18 to 91 years. Our analysis reveals that cognitive health declines non-linearly with age. While accounting for this pattern, we also find a clear socio-economic gradient; a higher socio-economic position is associated with better cognitive health. Moving beyond both gradients, we show that, large differences between individuals remain, which are related to environmental, health-behavioural, and psychosocial factors. We decompose this persisting variation in cognitive scores into different components using a Shapley decomposition. We find that age and education have the highest explanatory power. Nonetheless, environmental factors become increasingly more important as individuals get older, in some cases matching or even surpassing education in explanatory power.