The Neurocognitive Study for the Aging: Longitudinal Analysis on the Contribution of Sex, Age, Education and APOE ɛ4 on Cognitive Performance

Abstract

Objective: The effects of normal cognitive aging on executive functions (EF), Verbal Episodic Memory (VEM) and the contribution of age, sex, education, and APOΕ ε4 in a group of old Greek Cypriots across a five-year period were investigated.Design: NEUROAGE, the first project on cognitive aging in Cyprus, is a prospective longitudinal study with a rolling admission process. Participants are assessed at baseline and retested every 24–30 months.Subjects: 170 participants completed all three testing cycles; 86 men and 84 women with ages ranging between 60 and 88 years (mean = 73.21, SD = 5.84); education, 2–20 years (mean = 9.07, SD = 4.27).Results: Α Repeated Measures Multivariate Analysis of Covariance was conducted with one between-subject factor: sex; two covariates: age and education, while Time (time 1, time 2, time 3) served as a within – subject factor. Time did not have an effect on mini mental status examination in Greek (MMSE), EF or VEM. Also, sex had no effect on MMSE, EF and VEM. There was no time by sex interaction. Age and Education significantly predicted the EF performance, F(1, 168) = 11.23, p < 0.05; F(1, 158) = 90.03, p < 0.001 and VEM performance, F(1, 171) = 17.22, p < 0.001; F(1, 171) = 61.25, p < 0.001. Furthermore, there was a significant interaction effect between time and education, for EF, F(2, 167) = 7.02, p < 0.001. Performance of the APOE ε4 carriers did not differ on any of the above measures as compared to performance of non-carriers in this older adult group.Conclusion: Cognitively healthy adults maintained overall cognitive performance across the five-year period. Male and female participants performed similarly and the pattern of change over time was similar across the two sexes. Education was predictive of VEM and EF performance across time. Furthermore, those with higher education maintained higher levels of EF performance. APOE results did not differentiate performance at baseline. Implications of findings are discussed.

Regional Brain Volume, Brain Reserve and MMSE Performance in Healthy Aging From the NEUROAGE Cohort: Contributions of Sex, Education, and Depression Symptoms

“…Additional analyses incorporating T2-weighted images to study white matter hyperintensities could provide information on vascular dementia pathology in addition to volume atrophy associated more with AD pathology. As previously reported, in our NEUROAGE cohort, cognitive stability was demonstrated up to 5 years post baseline assessment on verbal episodic memory and executive functioning tasks in addition to gross cognitive measures like the MMSE (Chadjikyprianou et al, 2021 ). Finally, considering the exploratory nature of this study, the α-level remained at 0.05.…”

“…It explores modifiable and unmodifiable factors that contribute to cognitive health in the Greek-Cypriot population of Cyprus with its unique social-cultural, linguistic and genetic characteristics (Constantinidou et al, 2012 ; Giogkaraki et al, 2013 ; Demetriou and Constantinidou, 2018 ; Philippou et al, 2018 ). The present study contributes to the existing body of literature on determining the contributions of modifiable (education, depression) and unmodifiable (sex, age) risk factors on brain volume and brain health in this cognitively healthy and genetically homogeneous Mediterranean cohort with its unique social and geopolitical characteristics (Chadjikyprianou et al, 2021 ).…”

“…While participants of the present study were healthy older adults who had been followed in our project for several years through our longitudinal cognitive testing, it is possible that some of them experienced pathological changes without overt clinical symptoms. Our most recent study analyzing our longitudinal data indicates that education affects cognitive performance, but does not affect the rate of change in measures of general cognitive screening like the MMSE across a 5-year period for cognitively healthy NEUROAGE participants (Chadjikyprianou et al, 2021). As the NEUROAGE database continues to grow, future studies should investigate the link between BR and CR in our longitudinal cohort.…”

“…Study participants were community dwellers living independently, who were born and raised in a small Mediterranean island country with its unique geopolitical, social-cultural, and genetic characteristics. As noted in previous publications stemming from NEUROAGE (Philippou et al, 2018 ; Chadjikyprianou et al, 2021 ), the project has been able to capture the last generation of Cypriots who have attended very little formal schooling. Following the establishment of the Republic of Cyprus in 1960, public education has been free and mandatory through grade 9 or age 15.…”

Socioeconomic status impacts cognitive and socioemotional processes in healthy ageing

“…While the SES impact on social cognition has not been formally tested in the elderly, there is evidence of a positive relationship between education (one component of SES) and ToM abilities in this population 10 . Given the strong effect of education on cognitive 25 , 26 and executive 26 , 27 functions, and the reliance of social cognition on those processes 9 – 12 , a mediation effect would be expected. Indeed, low-SES middle-aged adults show preserved—or even heightened—socioemotional skills such as emotion recognition, empathy, and cooperation, putatively related to its adaptative value in adverse contexts 28 – 30 .…”