Lifestyle activities, mental health and cognitive function in adults aged 50 to 90 years

This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel UniversityIn a series of studies, lifestyle activities, mental health and aerobic fitness were investigated in relation to mean RT and response time variability (trial-to-trial variability in RT performance) obtained from a battery of cognitive measures in 257 healthy adults aged 50 to 90 years (M = 63.60). Cognition was assessed across four domains; psychomotor performance, executive function, visual search and word recognition. Hierarchical multiple regression analyses and structural equation modelling (SEM) were used to explore associations between age and outcome measures in a mediated-moderator analysis. The dedifferentiation of cognition and the dissociation between the outcome measures of mean RT and response time variability was also explored. Additionally, the neural correlates of response time variability were investigated using functional magnetic resonance imaging (fMRI). The findings indicated that poor mental health was associated with greater within-person (WP) variability and slower mean RTs and that this effect was greater in older adults. Higher lifestyle activity scores and higher aerobic fitness (VO2max) attenuated negative age gradients in WP variability and mean RT. Analyses suggested that the above effects were mediated by executive function. There was no evidence of dedifferentiation across cognitive domains and there was selective dissociation between the measures of mean RT and WP variability. The fMRI results suggested that WP variability was associated with fluctuations in executive control and, relatedly, attentional lapses. Overall, the findings suggest that executive function mediates a substantial portion of age-related variance in cognition and that this association is influenced by moderators such as an active lifestyle, aerobic fitness and mental health. The findings underline the potential benefits and importance of interventions to help maintain and promote mental health, and active lifestyles, in old age

Aerobic Fitness and Intraindividual Reaction Time Variability in Middle and Old Age.

Objective: To examine whether aerobic fitness moderated age differences in within-person reaction time variability (WP RT variability) and given conceptual linkage involving the frontal cortex, whether effects were mediated by executive function. Method: Aerobic fitness (estimated VO2max) and WP RT variability were investigated in 225 healthy, community-dwelling adults aged 50-90 years (M = 63.83) across 4 cognitive domains; psychomotor performance, executive function, visual search, and recognition. Results: Significant Age × Aerobic fitness interactions were found in relation to WP variability in 3 cognitive domains: psychomotor performance (4-choice RT), executive function (Flanker and Stroop arrows), and immediate recognition. Lower aerobic fitness was associated with greater RT variability, and this effect increased with age. Additionally, some of these effects were mediated by executive function. Discussion: The findings suggest that aerobic fitness moderated the association between age and intraindividual RT variability, and that executive function selectively mediated that association. It is possible that aerobic fitness helps attenuate the neurobiological decline that contributes to cognitive deficits in old age and that WP variability is a measure that may be particularly sensitive to this effect

Dementias Platform UK (DPUK) Data Portal - supporting multi-modal data analysis, data linkage and real-world outcomes

DPUK relaunched the Data Portal in November 2017 to present openly available information on the data availability and technical capability of the Data Portal, which supports multi-modal research studies with various objectives from disease model validation to observation investigation. DPUK not only brings clinical data together from cohorts, but is now supporting multi-modal studies in genetics and imaging, as well as linkage opportunities to routine data using world-leading technical solutions to data sharing. The capacity, adaptability and sophistication of the UK Secure eResearch Platform which the Portal is housed on, allows for unprecedented levels of centralised access to rich cohort and routine data, which is consequentially leading to international collaboration and development ambition within epidemiology, bioinformatics, research methodology and technical research solutions. As of March 2018, DPUK is supporting 50 cohorts, 41 from the UK and 9 from across the rest of the world, alongside furthering links and access to routine data held in the UK and across the world. 20 research studies are underway, and the DPUK mission to enhance data science within dementia research is leading the conversation for developing a community of excellence in this field and across other research genres

Trajectories of organized activity participation among urban adolescents: Associations with young adult outcomes

Organized activity participation provides opportunities for adolescents to develop assets that may support favorable outcomes in young adulthood. Activity participation may be especially beneficial for marginalized youth because they are likely to face stressors that increase risk of negative outcomes. We used growth mixture modeling to identify activity participation trajectories among African American adolescents in an urban, disadvantaged community (Wave 1: mean age = 14.86 years, standard deviation = 0.64; 49% male, N = 681). We also investigated if young adult outcomes differed by participation trajectory subgroups, the results of which suggested that a 3‐class model best fit the data: low initial and decreasing levels of participation (74%); moderate initial and consistent (21%); and moderate initial and increasing (5%). Adolescents in the increasing class reported higher life satisfaction and lower substance use in young adulthood compared to the decreasing class. Youth who increase participation in activities over time may experience greater opportunities for building assets related to positive development that support health and well‐being into young adulthood.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136459/1/jcop21863.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136459/2/jcop21863_am.pd

Poorer mental health is associated with cognitive deficits in old age

Few studies have examined the association between within-person (WP) reaction time (RT) variability and mental health (depression, anxiety, and social dysphoria) in old age. Therefore, we investigated mental health (using the General Health Questionnaire) and cognitive function (mean RT or WP variability) in 257 healthy, community-dwelling adults aged 50-90 years (M = 63.60). The cognitive domains assessed were psychomotor performance, executive function, visual search, and recognition. Structural equation models revealed that for WP variability, but not mean RT, poorer mental health was associated with visual search and immediate recognition deficits in older persons and that these relationships were partially mediated by executive function. The dissociation between mean RT and WP variability provides evidence that the latter measure may be particularly sensitive to the subtle effects of mental health on cognitive function in old age

Evaluating the harmonisation potential of diverse cohort datasets

Data discovery, the ability to find datasets relevant to an analysis, increases scientific opportunity, improves rigour and accelerates activity. Rapid growth in the depth, breadth, quantity and availability of data provides unprecedented opportunities and challenges for data discovery. A potential tool for increasing the efficiency of data discovery, particularly across multiple datasets is data harmonisation.A set of 124 variables, identified as being of broad interest to neurodegeneration, were harmonised using the C-Surv data model. Harmonisation strategies used were simple calibration, algorithmic transformation and standardisation to the Z-distribution. Widely used data conventions, optimised for inclusiveness rather than aetiological precision, were used as harmonisation rules. The harmonisation scheme was applied to data from four diverse population cohorts.Of the 120 variables that were found in the datasets, correspondence between the harmonised data schema and cohort-specific data models was complete or close for 111 (93%). For the remainder, harmonisation was possible with a marginal a loss of granularity.Although harmonisation is not an exact science, sufficient comparability across datasets was achieved to enable data discovery with relatively little loss of informativeness. This provides a basis for further work extending harmonisation to a larger variable list, applying the harmonisation to further datasets, and incentivising the development of data discovery tools

Dementias Platform UK (DPUK) Data Portal - World-leading infrastructure facilitating innovative multi-modal research

Introduction Modern team science requires effective sharing of data and skills. The DPUK Data Portal is a collection of tools, datasets and networks that allows for epidemiologists and specialist researchers alike to access, analyse and investigate cohort and different modalities of routine data across UK and international sources. Objectives and Approach The Portal is housed on an instance of UKSeRP (UK Secure eResearch Platform), that allows customisable infrastructure to be used for multi-modal research (thus far live in genetics, imaging and clinical data) for researchers across the world using remote access technology whilst allowing governance to remain with the data provider. A central team at Swansea University is responsible for data curation and processing, and runs an access procedure for researchers to apply to use data from multiple sources to be analysed in a central analysis environment. Other modalities are similarly hosted, with input from partner sites in Cardiff and Oxford. Results DPUK facilitates data access and research on 49 cohorts, 40 UK-based and 9 international. The centralised repository model including remote access and ability to store and make available different modalities of data, from phenotypic data, to genetic and imaging data, has allowed DPUK to begin to support research of varying topics, from those studying cognitive decline and Dementia as a disease, to those maturing analytical models. By providing access to data platforms specialising in genetics, imaging and routine clinical data, as well as to specialists in disease and biology to aid with its understanding, DPUK has realised a large-scale research exercise combining major data modalities on a central platform, and allow access to such rich data across the world under an umbrella of robust governance. Conclusion/Implications Globally, cohorts are pooling data, expertise and desire to enrich their own aims in partnership with a federated research community to enable in-depth scrutiny of the biological origins of dementia and the development and evaluation of novel approach to disease prevention and cure

Data Services for Cohort Studies: Increasing the impact of existing research studies and epidemiological readiness

Introduction The Dementias Platform UK (DPUK) Data Portal is a secure, accessible environment facilitating provision of rich data towards the largest Dementia, cognition and ageing community of cohort studies in the world. DPUK is also providing services for cohort studies and researchers to maximise the research potential of the programme’s community. Objectives and Approach As part of the engagement of DPUK cohorts with the Data Portal, cohorts will upload data onto the DPUK instance of UK Secure eResearch Platform infrastructure. The Data Portal allows access to a collaborative working space that allows cohorts to enrich their own data, perform their own analysis, and enhance the research potential of their data whilst making use of expertise at various DPUK sites, such as data linking, curation and multi-modal specialism. Cohort data divided into ontologies allows researchers to access data specific to their study needs and can be requested from multiple cohorts simultaneously. Results By utilising the Data Portal researchers have access to cohort data that has been prepared for dementia epidemiology using the agreed ontologies, providing more rapid access to cohort data that otherwise may be large and complex. The knowledge and experience of DPUK staff and collaborators can also help to guide nascent cohorts and feasibility studies into producing research-ready datasets, enabling them to achieve greater impact with their data. A range of analytical tools are provided on the Data Portal making analysis of a cohort’s own data or multiple independent datasets more accessible. Alongside data curation, DPUK also facilitates data linkage to routine sources, beginning with a Wales-wide use case that will expand to the UK over the course of the project. Conclusion/Implications Data from international sources accessible using a central platform permits international collaboration, with ontologies allowing previously disparate data to be combined and analysed to build knowledge and research impact. DPUK projects create policy leading results and operational research standards, enhancing cohort impact and discovery of benefits for Dementia patients