Who are the partners in the NCDC?

Seven Dutch university medical centres (UMCs) and the RIVM are collaborating within the NCDC. The consortium is funded by ZonMw (the Memorabel Programme) and Alzheimer Nederland.

NCDC stands for Netherlands Consortium of Dementia Cohorts. The research will run until July 2025. After that, the research will continue, including within the Netherlands Cohort Consortium.

Who’s who?

Prof. Dr Pieter Jelle Visser and Prof. Dr Arfan Ikram jointly lead the NCDC consortium. The research is divided into seven so-called work packages (more on this under ‘What kind of research?’).

The leaders of these work packages are Prof. Philip Scheltens, Prof. Martijn Huisman and Dr Almar Kok; Prof. Dr Eline Slagboom, Dr Mirjam Geerlings, Prof. Dr Peter De Deyn, Prof. Dr Monique Verschuren, Prof. Dr Edo Richard and Prof. Dr Wiesje van der Flier.

Within this consortium, the RIVM plays a key role in disseminating and implementing the results.

Collaborating partners

• Amsterdam UMC (Amsterdam Dementia Cohort, EPAD+ and Longitudinal Aging Study Amsterdam)
• Erasmus MC (Rotterdam Study)
• Leiden University Medical Centre (Leiden Longevity Study)
• Maastricht UMC+ (Maastricht Study)
• IVM (Doetinchem Cohort Study)
• Groningen University Medical Centre (Lifelines)
• UMC Utrecht (SMART-MR Study)

Find out more about the Memorabel Programme on Zonmw.nl.

Understanding the mechanisms for better prediction, prevention and treatment of dementia

Habits that increase the risk of dementia cause brain damage that leads to the condition. But how exactly? Is this visible? And can it be predicted? That is what the NCDC is investigating.

NCDC is combining existing data from seven cohort studies (population-based studies) and then seeking the answers. The research is divided into six substantive work packages.

First, making the data accessible

Merging large quantities of existing data is a major undertaking. All the data from the seven cohort studies must be harmonised. And an infrastructure must be put in place to merge, share and analyse that data. This is being done within this work package.

How exactly does dementia develop?

Certain lifestyle habits, such as smoking, a lack of physical activity and being overweight, increase the risk of dementia. Using the cohort data, the NCDC is investigating the mechanism by which such habits cause the brain damage that leads to dementia. The NCDC is also examining how the effects of the various habits accumulate, and what role heredity plays in brain deterioration.

Link between risk factors and signs of dementia

Signs of dementia are often already present in the brain before any symptoms appear. These include protein build-up or reduced blood flow. But what influence do risk-increasing habits, heredity and the environment each have, individually, on these signs of the disease? And are there certain groups of people who are more likely to develop them? The NCDC is also seeking answers to these questions.

Uncovering the bigger picture

In the brain of someone with dementia, several disease processes usually occur simultaneously. These include inflammation, protein clumps and disrupted connections between nerve cells. Much research focuses on just one of these processes. As a result, we may be missing ‘the bigger picture’. By combining data, the NCDC aims to discover exactly how these disease processes are interlinked and how they lead to memory problems.

In this research programme, the NCDC is also exploring new ways to detect different forms of dementia. For example, by analysing substances in the blood, known as biomarkers. This could make it easier to diagnose dementia in the future.

Better predicting dementia and taking action

Research findings provide answers to questions about just one small aspect of dementia. As a result, it is still difficult to accurately predict who is at risk of dementia, when to intervene, and what that means for care provision. The NCDC is taking a step in this direction by integrating the findings from all research packages into a single predictive model.

Ensuring that knowledge is put to practical use

NCDC is looking for ways to actively share knowledge with those who can benefit from it, such as healthcare professionals, policymakers and other researchers.

See also the project information about NCDC on zonmw.nl.

Bringing data together and analysing it

The NCDC aims to find answers by combining existing data from seven cohort studies. To this end, the NCDC is first investigating how to combine these data in such a way that very different types of data can be analysed together. This includes data on memory, behaviour, brain scans, blood test results and heredity.

Harmonising data

The first step is to harmonise the data: ensuring that information from different studies is interpreted in the same way. For example: checking whether memory problems have been measured and analysed in the same way. Researchers align their analytical methods and make data from different systems accessible, so that the data becomes comparable, usable and discoverable, and can be shared remotely (FAIR data) – within the legal frameworks for data exchange.

Building computational models

The NCDC brings together data on risk factors in a computational model to map the relative influence and cumulative effect of risk factors on brain damage and dementia. These include smoking, diet, social factors, heredity and environmental influences.

Combining and comparing data

The seven cohort studies that the NCDC is combining also include existing brain scans, blood test results and cognitive tests. Researchers are combining this data to determine how risk factors are linked to changes in the brain, behaviour and the blood. For example, they are comparing the point at which brain damage becomes visible with the results of cognitive tests. They are also investigating whether these changes reinforce one another.

The NCDC is also examining data on substances present in the blood and the brain, and when they occur. It is comparing this with data on brain damage and behavioural symptoms associated with depression. Researchers hope this will lead to the discovery of new biomarkers: substances that can help identify dementia at an earlier stage.

Statistics and AI

The NCDC combines all the insights from the research packages into a single mathematical model. This model illustrates how risk factors, brain changes and biomarkers are linked to the risk of dementia.

To develop the model, researchers are using statistical analyses and machine learning (a technique from the field of artificial intelligence, AI). To verify that the model is accurate and reliable, the NCDC is testing it using data from studies other than the seven cohort studies.

Practical knowledge for prevention and policy

The NCDC provides insights into risk factors for dementia and what can be done about them at any given stage. It then translates this knowledge into resources for researchers, policymakers and healthcare professionals, such as tools, policy recommendations and publications.

Harmonised data

The NCDC has succeeded in harmonising data from nine Dutch cohorts relevant to dementia research with the OMOP CMD (Observational Medical Outcomes Partnership Common Data Model). This makes it possible to identify significant associations, for example, with rare symptoms and diseases. In collaboration with DEMPACT, the NCDC shares the scripts and mappings for this purpose with other researchers on Zenodo.com.

In addition, NCDC has produced a manual containing detailed guidelines for the harmonisation of cognitive data from the nine Dutch cohorts. This has also been published on Zenodo.com.

Models that provide insight

NCDC uses all the data from the seven cohort studies to create clear mathematical models. These show how everything is interconnected: heredity, lifestyle, environmental factors, blood and brain data – and the risk of dementia.

Policy advice for effective prevention

If, for example, it emerges that certain groups are at increased risk of dementia, the NCDC can advise policymakers to target prevention specifically at those who need it most. This enables the government or healthcare organisations to work and invest more effectively, and make a greater difference.

Impact analyses

The NCDC also intends to carry out impact analyses. This involves using the model to calculate how many people’s dementia can be prevented if a particular risk factor is addressed at a specific point in time. Examples include treating high blood pressure or depression at an earlier stage. This will enable policymakers and healthcare professionals to identify what they should prioritise and which approach yields the greatest benefits.

Dementia risk test

The NCDC has demonstrated that the presence of the protein amyloid in the brain is the strongest predictor of cognitive decline. Furthermore, certain substances in the blood appear to indicate the presence of amyloid in the brain.

Such new biomarkers can be used to develop tests that can detect an increased risk of dementia or better predict its progression. This enables doctors to intervene earlier or provide better support. At present, a test exists that can measure abnormal amyloid levels for scientific research purposes. Participants will only be informed of any abnormal results if they indicate in advance that they wish to know.

Scientific publications

The NCDC publishes the results of the research projects in scientific journals. More than 10 publications have already appeared. For an up-to-date overview, see: Alzheimercentrum.nl.

Together with the target group

In what is known as a user committee, people with dementia (and their loved ones), care professionals and policymakers contribute their ideas to the NCDC.

For example, the committee helps shape the direction and relevance of the research. What knowledge, for instance, is important for practitioners to know? Where should the research be heading to make a real difference? The committee meets several times a year and provides feedback on the research programme.