Numerous lifestyle, cardiovascular, and psychosocial factors have been implicated in the development of cognitive decline and dementia. Using a person-centered approach, this study explored...Show moreNumerous lifestyle, cardiovascular, and psychosocial factors have been implicated in the development of cognitive decline and dementia. Using a person-centered approach, this study explored clustering of modifiable risk factors for cognitive decline and dementia and investigated how these clusters are associated with declines in cognition and with dementia risk. Here, cognitive decline was operationalized as declining information processing speed. The sample consisted of 3787 older adults (age 55-85) enrolled in the Longitudinal Aging Study Amsterdam. Latent class analysis was performed over a subset of 14 lifestyle, cardiovascular, and psychosocial risk factors to identify latent subgroups. Latent growth curve modelling associated membership in identified subgroups with trajectories of processing speed. Logistic regression associated group membership with incidence of probable dementia (n=2611). A four-class solution was deemed to optimally represent the sample. Next to a large group with no specific salient features (n=845, 75.1%), other groups reflected pronounced depressive symptoms (n=324, 8.6%), cardiometabolic risk (n=410, 10.8%), and high physical activity (n=208, 5.5%), respectively. Latent growth curve modeling suggested that declines in processing speed accelerated with age, but latent class membership did not seem to affect these declines. Compared to the normative group, the depressed group had lower initial levels of processing speed (β_intercept=-2.38; 95% CI=[-3.38, -1.37]; p<.001), but further trajectory differences between latent classes were not statistically significant at α=5%. No significant differences in odds of probable dementia between the normative and other groups were found. Thus, this study did not find evidence of an effect of membership in identified latent classes on the strength or rate of cognitive decline, nor dementia. To draw implications for clinical and political decision-making, future research could test the robustness of findings by replicating analyses in similar cohorts, examine the utility of other grouping structures, consider inclusion of alternative risk factors, and investigate auxiliary outcome measures of cognitive decline and dementia.Show less
Abstract Working memory performance declines naturally in people as they get older. However, much variation exists between people in the degree to which their working memory deteriorates. Knowing...Show moreAbstract Working memory performance declines naturally in people as they get older. However, much variation exists between people in the degree to which their working memory deteriorates. Knowing the risk-factors associated with higher or lower working memory performance could help mitigate some of the negative effects that are experienced by people as such. There are many known predictors for lower working memory performance identified by the literature, such as age, education, cigarette smoking, alcohol consumption, and history of concussion. The aim of this study is to investigate the relationship of these predictors with working memory performance to identify which of these variables most strongly predict performance on a working memory test. Identifying the most prominent risk-factors associated with lower working memory performance can aid the development of specific tools and treatments for counteracting working memory deterioration as people get older. We included 132 subjects from the general population and measured working memory performance using a computerized OSPAN test. The predictors were measured using different self-report questionnaires, regarding demographics and general health. Linear regression models were then used to test each variable as a predictor of working memory performance. The total sample consisted of 49 males and 83 females with a median age of 44.5, and a mean education level of 4.97 years of education. Our analysis demonstrated that education level was positively associated with working memory performance (p = 0.008, F(1, 129) = 7.23, adjusted R2 = 0.05 ), whereas the other variables did not show a relationship with working memory. This result shows education level to be a significant determiner of higher or lower performance of working memory. However, the small effect size (0.05) makes it difficult to say whether education level makes much difference when generalizing to the general population. Furthermore, the influence of age, alcohol consumption, cigarette smoking, and history of concussion on working memory performance was not confirmed in this sample. The influence of these variables on working memory performance may only appear under different conditions, such as only in older participants or in participants that smoke or drink more frequently.Show less
Abstract Alzheimer's Disease (AD) pathology is characterized by the accumulation of amyloid-beta (Aß) plaques and tau tangles, leading to cognitive decline. Cognitive reserve (CR), in this study...Show moreAbstract Alzheimer's Disease (AD) pathology is characterized by the accumulation of amyloid-beta (Aß) plaques and tau tangles, leading to cognitive decline. Cognitive reserve (CR), in this study estimated by educational level, is believed to mitigate the impact of these pathologies on cognitive function. This study hypothesized that at similar levels of amyloid and tau built-up, people with higher educational level show less cognitive decline overtime compared to people with lower educational level. For this we used a preclinical sample, as the non-symptomatologic stage is understudied. In a prospective study design, 217 cognitively healthy monozygotic twins over the age of 60 (mean age = 70.79, SD = 7.96) from the Netherlands Twin Register were analysed. Aß levels were assessed using PET imaging, while tau levels were measured via cerebrospinal fluid (CSF) analysis. Cognitive performance was evaluated at baseline and through three follow-up assessments over approximately six years. Linear Mixed Models (LMMs) results indicated a significant association between higher Aß levels and memory decline, with no significant impact on attention, language, or executive functioning. Higher tau levels were associated with declines in memory, attention, and language. Contrary to expectations, CR did not moderate the relationship between AD biomarkers and cognitive decline. These results suggest that while Aß and tau are linked to cognitive decline, CR estimated through educational attainment, does not provide significant protective effects in the preclinical stages of AD. This may be due to disproportionate biomarker distribution across educational groups, small sample sizes in lower education groups, and the study's cross-sectional and global biomarker measurements. Layman’s Abstract: De ziekte van Alzheimer leidt tot geheugen- en denkproblemen als gevolg van schadelijke eiwitten in de hersenen. In deze studie werd onderzocht of hoger onderwijs, waarvan gedacht wordt dat het de cognitieve reserve vergroot, bescherming kan bieden tegen deze effecten. We bestudeerden 217 gezonde oudere tweelingen en ontdekten dat hogere niveaus van deze eiwitten verband hielden met een afname van het geheugen en andere cognitieve vaardigheden. Verrassend genoeg kon hoger onderwijs deze achteruitgang niet voorkomen, wat erop wijst dat onderwijs alleen, mogelijk geen bescherming biedt tegen de vroege tekenen van de ziekte van Alzheimer.Show less
