Ongoing research in the Cognitive Ageing project

A selection of projects we are currently working on

  • Determinants of cognitive trajectories over 15 years in a low-educated sample (lead: Fabiana Ribeiro)
  • The impact of participating in the labour market at advanced ages (65+) on cognitive performance in South Korea and the U.S. (lead: Jung Hyun Kim), see the pre-print here.
  • Contextual-level gender inequalities to explain gender differences in older-age cognitive functioning (lead: Ariane Bertogg)
  • Probable dementia algorithms for the Survey of Health, Ageing and Retirement in Europe (lead: Matthias Klee)
  • The associations between microbiome characteristics and dementia risk factors
  • Understanding how to best assess the effect of behavior changes on risk of dementia in observational studies
  • Dementia risk prediction with a focus on modifiable social and behavioural risk factors with statistical learning methods

Please get in touch for more information.

Mapping of machine learning approaches for description, prediction, and causal inference in the social and health sciences

Anja K. Leist, Matthias Klee, Jung Hyun Kim, David H. Rehkopf, Stéphane P. A. Bordas, Graciela Muniz-Terrera & Sara Wade
Science Advances

19 October 2022 https://doi.org/10.1126/sciadv.abk1942

Machine learning (ML) methodology used in the social and health sciences needs to fit the intended research purposes of description, prediction, or causal inference. This paper provides a comprehensive, systematic meta-mapping of research questions in the social and health sciences to appropriate ML approaches by incorporating the necessary requirements to statistical analysis in these disciplines. We map the established classification into description, prediction, counterfactual prediction, and causal structural learning to common research goals, such as estimating prevalence of adverse social or health outcomes, predicting the risk of an event, and identifying risk factors or causes of adverse outcomes, and explain common ML performance metrics. Such mapping may help to fully exploit the benefits of ML while considering domain-specific aspects relevant to the social and health sciences and hopefully contribute to the acceleration of the uptake of ML applications to advance both basic and applied social and health sciences research.

Figure (c) Matthias Klee, https://doi.org/10.1126/sciadv.abk1942

Prevalence of dementia in Latin America and Caribbean countries: Systematic review and meta-analyses exploring age, sex, rurality, and education as possible determinants

Fabiana Ribeiro, Ana Carolina Teixeira Santos, Paulo Caramelli, & Anja K. Leist
Aging Research Reviews

3 August 2022, https://doi.org/10.1016/j.arr.2022.101703

Fabiana Ribeiro is a postdoctoral researcher in the CRISP project.

What is the rate of dementia in Latin America and the Caribbean? What are the differences by sex/gender, education, and which risk factors are associated with cognitive impairment? Fabiana Ribeiro, postdoc researcher in the CRISP project, has led three publications to understand social and behavioral determinants of cognitive ageing in the lower-resource settings of Brazil and Latin America at large. This meta-analysis is the most comprehensive assessment of the prevalence of dementia in Latin America and the Caribbean.

Earlier research suggested that the prevalence of dementia in Latin America and the Caribbean (LAC) may be higher than in high-income countries. We explored sex, education and urban vs rural residence as determinants that may lead to this disparity in LAC countries. We searched Pubmed, Web of Knowledge, Scopus, Lilacs, and SciELO for studies on dementia in LAC countries published in English, Spanish, and Portuguese. Random-effects models were applied.

Thirty-one studies from 17 LAC countries were included. Pooled prevalence of all-cause dementia was 10.66%. Further analyses with studies providing raw prevalence by sex, area, and educational level showed a higher prevalence for women (8.97%) than for men (7.26%). Also, dementia prevalence was higher for rural than urban residents (7.71% vs 8.68%, respectively). Participants without formal education presented more than double the prevalence of dementia (21.37%) compared to those with at least one year of formal education (9.88%). Studies with more recent data collection showed higher dementia prevalence.

Our findings suggest a high global dementia prevalence in LAC countries and an unequal burden of dementia for women, lower-educated, and rural residents. Secular increases in dementia prevalence call for greater public health efforts for preventative actions.

This study has been published as pre-print: https://www.medrxiv.org/content/10.1101/2021.10.15.21265054v1

Childhood Socioeconomic Disadvantage and Pathways to Memory Performance in Mid to Late Adulthood: What Matters Most?

Katherine J. Ford, Lindsay C. Kobayashi, & Anja K. Leist
Journals of Gerontology: Social Sciences

18 May 2022, https://doi.org/10.1093/geronb/gbac075

Code on GitHub

Katherine Ford is a postdoc at Carleton University who did her PhD affiliated with the CRISP project at the Doctoral Training Unit MINLAB. This is one of the three papers constituting her PhD project.

Adults who grew up in disadvantaged childhood conditions consistently show lower cognitive function in later life. Katherine investigated which aspects of childhood socioeconomic disadvantage were most relevant for memory performance in mid-to-late adulthood, namely, lower-skilled occupation of the primary breadwinner, having few books in the home, overcrowding in the home, and lack of water and heating facilities in the home.

Using the g-formula, she could test for direct and indirect effects through education and occupation. We used data from the English Longitudinal Study of Ageing (n=4,553). The findings show that few books were the most consequential component of childhood socioeconomic disadvantage for later life memory. The total effect of a breadwinner in lower-skilled occupations was smaller but not significantly different from few books, while it was significantly smaller with overcrowding. The latter two total effects were mostly mediated by education and occupation.

We conclude that a literate environment in the childhood home may have lasting direct effects on memory function in mid-to-later life, while parental occupation and overcrowding appear to influence memory primarily through educational and occupational pathways.

The prevalence of mild cognitive impairment in Latin America and the Caribbean: a systematic review and meta-analysis

Fabiana Ribeiro, Ana Carolina Teixeira Santos, and Anja K. Leist
Aging & Mental Health

29 November 2021 https://doi.org/10.1080/13607863.2021.2003297

Fabiana Ribeiro is a postdoctoral researcher in the CRISP project.

What is the rate of mild cognitive impairment (MCI) and dementia in Latin America and the Caribbean? What are the differences by sex/gender, education, and which risk factors are associated with cognitive impairment? Fabiana Ribeiro, postdoc researcher in the CRISP project, has led three publications to understand social and behavioral determinants of cognitive ageing in the lower-resource settings of Brazil and Latin America at large.

In a systematic review on the prevalence of mild cognitive impairment, we find comparatively higher prevalence of MCI in Latin America compared to estimates from higher-income countries, with older and lower-educated individuals showing higher prevalence.

Why do we want to know more about the prevalence of mild cognitive impairment? People with MCI are at high risk of progressing to dementia and thus represent a group that could potentially benefit strongly from brain health interventions.

In another publication, we assessed the prevalence of dementia in Latin America and the Caribbean, exploring sex, education and urban vs rural residence as determinants. This publication is currently available as pre-print here: https://www.medrxiv.org/content/10.1101/2021.10.15.21265054v1

Changes in prevalence of cognitive impairment and associated risk factors in São Paulo, Brazil, 2000-2015

Fabiana Silva Ribeiro, Yeda Aparecida de Oliveira Duarte, Jair Lício Ferreira Santos, & Anja K. Leist
BMC Geriatrics

27 October 2021 https://doi.org/10.1186/s12877-021-02542-x

Fabiana Ribeiro is a postdoctoral researcher in the CRISP project.

With data from São Paulo, we have investigated the prevalence of cognitive impairment over a period of 15 years (2000-2015). In contrast to other studies from higher-resource settings and despite increases in educational attainment, we don’t find secular increases in the prevalence of cognitive impairment, Further, we find increases in disease burden in hypertension, diabetes, and overweight/obesity, which have been found to increase risk of cognitive impairment and dementia. Women showed higher disease burden, possibly related to gender-role attitudes and fewer opportunities to build up cognitive reserve. Individuals self-identifying as black also showed more disadvantaged health profiles, possibly related to structural discrimination leading to lower quantity and quality of education and less advantaged socioeconomic conditions.

Inequality of educational opportunity at time of schooling predicts cognitive functioning in later adulthood

Anja K. Leist, Eyal Bar-Haim, Louis Chauvel
SSM – Population Health

September 2021, https://doi.org/10.1016/j.ssmph.2021.100837

Code on Github

Highlights

Macro-level determinants of older-age cognitive functioning need to be better understood.

The role of inequality of educational opportunity at time of schooling (IEO) for later-life cognition is not yet clear.

In a sample from 16 European countries and Israel, higher IEO predicted lower later-life cognitive functioning.

Particularly women with lower education of the cohorts under investigation seem to have been vulnerable to higher IEO.

 

Picture (c) https://geheimtipp-leipzig.de/klassenfoto-aus-den-1950ern/

Changes in neighborhood-level socioeconomic disadvantage and older Americans’ cognitive functioning

Settels, Jason, and Leist, Anja
Health & Place

Volume 68, March 2021, 102510, https://doi.org/10.1016/j.healthplace.2021.102510

Jason Settels is a postdoctoral researcher at the Institute for Research on Socio-Economic Inequality at the University of Luxembourg.

Main code on GitHub

Neighborhood socioeconomic conditions have an impact on cognitive abilities at older ages, mediated through more proximate factors such as social capital, community involvement, size of close networks, social support, poverty, consumption of alcohol and smoking. Neighborhood disadvantage causes distress and depression. As an example: living in a disadvantaged neighborhood goes along with a restricted social network with weaker ties. Health and cognitive functioning, however, are improved by having a strong social network with strong ties. These factors and their interaction, however, may additionally be modified by individual levels of education. It has been shown that higher education is associated with better cognitive health, as an indicator of early-life cognitive development.

Adopting a dynamic perspective in a U.S. American community sample (NSHAP) to address possible reverse causality, this study hypothesized that worsening neighborhood socioeconomic circumstances are associated with stronger declines in older residents’ cognitive functioning over time. We tested if this relationship may be mediated through different neighborhood and individual-level social and health factors, and if education would play a role in modifying these relationships.

We find that worsening neighborhood socioeconomic conditions go along with decreases in cognitive functioning of older adults. Changes in number of depressive symptoms, size of close networks and physical activity mediate the effect of worsening neighborhood socioeconomic conditions, in a moderate way. We conclude that personal characteristics seem to contribute more to explaining the effects of worsening neighborhood conditions than the investigated contextual characteristics. Having a university degree or not did not moderate the relationship between worsening socioeconomic neighborhood conditions and cognitive decline.

Improving neighborhood socioeconomic conditions may have a positive effect for the cognitive health of older adults. Possible areas of policy interventions may be involving older people in community groups and activities, to improve their social networks, engage in physical activity and ideally decrease depressive symptoms.

 

Returns to Educational and Occupational Attainment in Cognitive Performance for Middle-Aged South Korean Men and Women

Ford, Katherine, and Leist, Anja
Gerontology and Geriatric Medicine

21 March 2021. DOI: 10.1177/23337214211004366

Katherine Ford, MPH, is a doctoral student in Social Sciences, in the Doctoral Training Unit on Migration, Inequalities, and Labour Markets (MINLAB) at the University of Luxembourg.

Code on GitHub

Background: Gender differences in late middle-age cognitive performance may be explained by differences in educational or occupational attainment rates, or gender-patterned returns of similar education and occupation to cognitive reserve. We tested these competing hypotheses in the historically highly gender unequal context of South Korea. Methods: Data came from the 2006 wave of the Korean Longitudinal Study of Aging. We included adults aged 45–65 years. Using quantile regression decompositions, we decomposed cognitive performance differences across quantiles into differences due to rates of educational and occupational attainment and differences due to divergent returns to those characteristics. Results: Gender-based cognitive performance differences across deciles were driven by differences in rates of educational and occupational attainment, while the returns to these characteristics were similar for both genders. Conclusions: Findings suggest that educational and occupational characteristics contribute to cognitive performance similarly in men and women, but discordant rates of these characteristics contribute to performance gaps.

 

Partnership and Cognitive Aging in Europe: Mediating Factors and Social Stratification

Bertogg, Ariane, and Leist, Anja
The Journals of Gerontology: Social Sciences

2 February 2021. DOI: 10.1093/geronb/gbab020

Ariane Bertogg is a postdoctoral researcher at the University of Konstanz, Germany.

Living in a partnership has been shown to benefit later life health in general and decrease the risk of cognitive impairment. Few studies have, however, examined whether different types of partnership transitions also differ with respect to their impact on cognitive trajectories, and whether financial resources, healthy behaviors, cognitive stimulation, and social integration can explain these differences. With data from the Survey of Health, Ageing and Retirement in Europe, and employing fixed effects regression models, we sought to exploit individual-level variation in partnership and simultaneous cognitive changes.

Partnership status was stable in most respondents (around 90%). Compared to remaining partnered and after controlling for sociodemographic factors, transition to divorce was associated with a steeper decline in immediate and delayed recall. Exploring possible mechanisms, both financial resources and social integration, explained these differences. Additional analyses suggested that effects were mostly driven by individuals with lower education.

Partnership transitions remain infrequent events in later life, but our findings indicate that they can induce less favorable cognitive trajectories compared to partnered individuals, particularly for those with lower cognitive reserve.

 

Examining gender differentials in the association of low control work with cognitive performance in older workers

Ford, Katherine, Batty, G. David, and Leist, Anja
European Journal of Public Health, ckaa173, https://doi.org/10.1093/eurpub/ckaa173

Katherine Ford, MPH, is a doctoral student in Social Sciences, in the Doctoral Training Unit on Migration, Inequalities, and Labour Markets (MINLAB) at the University of Luxembourg.

Code on GitHub

We looked into perceived control at work, an important psychosocial work characteristic, and the extent to which changes in control at work influence performance on cognitive tests in older workers. High perceived control was associated with higher performance in verbal fluency.

We didn’t find solid sex/gender differences in how control relates to cognition. However, there are several differences between the genders in the context of control at work: Women and men of the cohorts under investigation had had different work trajectories, different career opportunities, and may have retired early for different reasons. Perceived (and actual) control at work is also different for men and women even in the same occupation. All these are potential sources of bias, which could have masked the findings.

 

Our poster on prevalence of cognitive impairment in Sao Paolo, Brazil, 2000-2015, at the AAIC, July 2020

Ribeiro, Fabiana, Duarte, Yeda, Santos, Jair, and Leist, Anja
Poster presentation (2020, July 30)

 

Our poster on physical activity changes and risk of cognitive decline and dementia at the AAIC, July 2020

Leist, Anja, Muniz-Terrera, Graciela, and Solomon, Alina
Poster presentation (2020, July 30)

Leist Research Group Manual

Leist, Anja
Manual (2019, December 12)

The manual should give team members all necessary information to carry out our day-to-day work and intends to put down in words our work and research principles. It refers to policies at our institution and global movements such as #OpenScience where applicable. The manual has been set up concurrently with the research group Anja has established after receiving an ERC Starting Grant for the CRISP project (no. 803239). The manual is partly a reflection of the highest research standards expected by the European Research Council, partly laying out the particular conditions at the University of Luxembourg, and a reflection of Anja’s vision of a healthy research environment. The manual is inspired by Mariam Aly’s lab manual.

Please get in touch for a copy.

Gender inequalities across the life course: A societal perspective on gender differences in dementia

Leist, Anja; Ford, Katherine
Presentation at Alzheimer Europe conference (2019, October 25)

Women are at increased risk of developing dementia, which can only partly be explained with differences in longevity, sex biology, or differences in detection/diagnosis. A promising approach at the population level is the systematic investigation of life course conditions for men and women across countries and cohorts in order to detect if schooling or work opportunities differ by gender. In the cognitive reserve framework, education and work reflect opportunities for cognitively stimulating activities, which increase cognitive reserve across the life course, and which could delay cognitive decline and the diagnosis of dementia. We develop a framework for systematizing gender inequalities across different life stages and life domains, with a focus on systematic disadvantages for women that could be relevant barriers to cognitive reserve development. The new framework leads to testable hypotheses in both the Western and global context regarding life-course socialization and schooling and work opportunities that have been different for men and women. We need to better understand how different life-course opportunities for men and women can create gender differences in dementia at old ages in order to identify individuals at risk today and improve conditions for future generations.

WYLD Special Symposium: Technological Innovations in Dementia Diagnosis and Care

Leist, Anja
Symposium (2019, October 24)
Speakers: Ríona McArdle, Newcastle University; Haza Newman, GerasSolutions Stockholm; Claire Lancaster, University of Oxford; Silka Dawn Freiesleben, Charité Berlin; Katarzyna Hess-Wiktor, Minnity Stockholm

Researchers and entrepreneurs present technological innovations in dementia diagnosis and care, particularly through the use of wearables, apps, and novel data analysis techniques. These innovations address complex challenges of differential dementia diagnosis and ensuring high-quality and safe home and formal care.

Dementia Research Forum Demenzforschungstage – Journées de recherche sur la démence 2019

Leist, Anja
Report on the “Dementia Research Forum” 2019. Involvement of persons living with dementia and their caregivers in research on cognitive ageing and dementia

available in French, German and English

On 19 and 20 September 2019, the first “Dementia Research Forum” took place at the Belval campus of the University of Luxembourg. People living with dementia, close relatives of persons living with dementia and professionals in the healthcare sector were invited to the university to discuss the research questions of the ERC-CRISP project and to advise the researchers on the research and dissemination of the research results. The idea of giving people affected by dementia a voice in research projects is already being successfully implemented in other countries such as the UK. The report presents some information on the research project for the general public and summarises the contributions of the participants.

The long-lasting impact of inequality of educational opportunities on later-life cognitive functioning

Leist, Anja; Bar-Haim, Eyal; Chauvel, Louis
Presentation (2019, September 14) at the ECSR Conference, Lausanne.

Social and behavioral factors in cognitive aging: Applying the causal inference framework in observational studies

Leist, Anja
Presentation (2019, May 25)

There is an urgent need to better understand how to maintain cognitive functioning at older ages with lifestyle interventions, given that there is currently no medical cure available to prevent, halt or reverse the progression of cognitive decline and dementia. However, in current models, it is still not well established which social and behavioral modifiable factors (e.g. education, BMI, physical activity, sleep, depression) matter most at which ages, and which behavioral profiles are most protective against cognitive decline. In the last years, advances in the fields of causal inference have equipped epidemiology and social sciences with methods and models to approach causal questions in observational studies. The presentation will give an overview of the causal inference framework to investigate the value of behavior changes in cognitive aging. Motivated by conflicting recent publications if physical activity should or should not be recommended to reduce individual risk of cognitive decline, we emulate a target trial where sedentary people are followed over the course of the Survey of Health, Ageing and Retirement in Europe (SHARE) and compare their cognitive development depending on initiating or not physical activity at a later measurement. Extended inclusion/exclusion criteria, and concepts of incident versus prevalent users and multiple eligibility are introduced. The causal inference framework applied to observational studies is able to guide study design to reconcile conflicting evidence from intervention and observational studies. Investigations under the new framework have fewer ethical considerations compared to intervention research and, considering the need to follow up individuals over several decades, are considerably more cost-effective. Limitations are discussed.

Symposium: Early detection and prevention of cognitive decline and dementia: Findings from major European collaborative and research initiatives

Leist, Anja
Symposium (2019, May 25)
Speakers: Craig Ritchie, University of Edinburgh; Alina Solomon, University of Eastern Finland; Graciela Muniz-Terrera, University of Edinburgh; Tom Russ, University of Edinburgh

With still no medical cure for dementia available, major research initiatives have been set up to investigate and target the development of dementia at earlier stages. Several ongoing projects focus on early detection of dementia with the hope to be able to administer personalized interventions for individuals at high risk. Ongoing clinical trials test different interventions on their potential to prevent or delay the onset of dementia. Complementing those efforts, large and long-spanning observational studies can be used to detect long-term precursors of cognitive aging. Indeed, there is increasing evidence for a large window of opportunity for intervention of several decades that could be used for preventative efforts in dementia. The symposium will bring together major European collaborative and research initiatives in the field of early detection and prevention of dementia. The first part of the symposium will present findings from clinical trials, the second part new findings coming from a range of observational studies. The first paper will report on the design and study cohorts of the European Prevention of Alzheimer’s Dementia Consortium (EPAD) and the TriBEKa project. The second paper will focus on new multifactorial models to quantify prevention potential based on the FINGER trial. The third paper will report an integrated analysis of four longitudinal studies of ageing (OCT0, H70, LASA, and MAP) to evaluate the role of cognitively stimulating activities in the transitions from cognitively normal to slightly impaired, severely impaired, and death with multi-state models. The fourth paper will present the contribution of environmental factors over the life course, in particular air pollution, on cognitive change in the Lothian Birth Cohort of 1936. The last paper makes use of recent developments in approaching causal inference in observational studies and applies these to predict cognitive aging and dementia with data from the Survey of Health, Ageing and Retirement in Europe.

New ERC Project on Cognitive Aging

Leist, Anja
Blog post (2018, July 27)

An overview of the objectives of the ERC-CRISP project for a general public.

On my personal website, you can also find information on earlier outreach activities such as a dementia conference and fundraiser, and dementia awareness workshops.