This paper investigates the relationship between the concept of activity (including both professional and nonprofessional) and cognitive functioning among older European individuals. In this research, we used data collected during the first wave of SHARE (Survey on Health, Ageing and Retirement in Europe), and a measurement approach known as stochastic frontier analysis, derived from the economic literature. SHARE includes a large population (n > 25,000) geographically distributed across Europe, and analyzes several dimensions simultaneously, including physical and mental health activity. The main advantages of stochastic frontier analysis are that it allows estimation of parametric function relating cognitive scores and driving factors at the boundary and disentangles frontier noise and distance to frontier components, as well as testing the effect of potential factors on these distances simultaneously. The analysis reveals that all activities are positively related to cognitive functioning in elderly people. Our results are discussed in terms of prevention of cognitive aging and Alzheimer’s disease, and regarding the potential impact that some retirement programs might have on cognitive functioning in individuals across Europe.

Present data further corroborate the view that leisure activities even in old age may lead to further enrichment effects and thereby may be related to better cognitive functioning. The role of engaging in activities in the context of major life events such as retirement is discussed.

This study is the first to show that it is of great importance to question methods measuring CR proxies in order to develop a clinical tool allowing a comprehensive and accurate estimation of CR.

ObjectivesTo test whether deferred retirement is associated with delayed onset of Alzheimer’s disease (AD), and, if so, to determine whether retirement age still predicts the age at onset of AD when two potential biases are considered.MethodsThe study sample was gathered from the Impact of Cholinergic Treatment Use/Data Sharing Alzheimer cohort (ICTUS/DSA), a European study of 1,380 AD patients. Information regarding retirement age, onset of symptoms and covariates was collected at baseline whereas age at diagnosis was gathered from the patient’s medical record prior to study entry. Linear mixed models, adjusted for gender, education, occupation, center, country, household income, depression and cardiovascular risk factors were conducted on 815 patients.Results(1) The global analyses (n = 815) revealed that later age at retirement was associated with later age at diagnosis (β = 0.31, p < 0.0001); (2) once the selection bias was considered (n = 637), results showed that this association was weaker but remained significant (β = 0.15, p = 0.004); (3) once the bias of the reverse causality (i.e., the possibility that subjects may have left the workforce due to prior cognitive impairment) was considered (n = 447), the effect was no longer significant (β = 0.06, p = 0.18).ConclusionThe present study supports that there is an association between retirement age and age at onset of AD. However, the strength of this association appears to be overestimated due to the selection bias. Moreover, the causality issue remains unresolved. Further prospective investigations are mandatory in order to correctly address this question.

Although our results are in accordance with previous studies (i.e., older age at retirement is associated with decreased risk of dementia), it provides additional information regarding the possible explanation for such results. Given that a longer working life did not reduce the risk of dementia, the age at retirement cannot be considered as a new factor of cognitive reserve but rather seems to be a psycho-social vulnerability factor. Further evidence is necessary to identify work and retirement related factors that influence the association between the age at retirement and the risk of dementia.