The first step consists of an online questionnaire asking for medical information and questions on demographics and socio-economics, well-being, quality of life, cognition, and sleep that may influence the risk of developing age-related diseases. The questionnaire takes around 45 minutes to complete. Please have information on your medication at hand as there are specific questions on the medication you are currently taking in the survey.

Based on the online questionnaire answers, the study team will contact a subset of participants to propose a smell test to be performed at home. Some of these participants may be invited to come to the clinic for a medical examination and to undergo other tests (see below). However, if you are contacted, it does not mean that you are at an increased risk, as we will contact participants with different risk scores (low- or high-risk).

Finally, if initial analyses of the overall data provide promising results, the study might be prolonged, and participants might be asked to repeat the online tests annually.

What happens if I am one of the participants invited for further examinations?

Participants invited to perform a smell test at home and/or undergo a medical examination will be contacted after an initial evaluation of the data. Participation is voluntary for all steps. If you are invited for an appointment at our Research Clinic in Strassen, in Luxembourg City, you will be invited to perform a clinical examination and donate samples:

• Medical interview;
• Medical examination;
• Olfactory tests and memory tests;
• Blood, saliva, and urine collection.

You will have the possibility to donate a stool sample as well. The clinical team will give you a dedicated collection kit to take home, with the help of which you can collect a small amount of stool and send it to us by mail.

For this part of our study, the clinical examination and sample collection will be in the context of the related established Biomaterial collection for neurodegenerative disease research (ND Collection), approved by the Ministry of Health and with a favorable opinion from the National Research Ethics Committee (CNER). This national research collection was established in 2015 by the Integrated BioBank of Luxembourg (IBBL), part of the Luxembourg Institute of Health (LIH), and the Luxembourg Centre for Systems and Biomedicine (LCSB), part of the University of Luxembourg (UL) in the context of the National Centre of Excellence in Research on Parkinson’s Disease (NCER-PD).

The ND Collection aims to collect clinical data and samples from individuals with and without neurodegenerative disease to answer the most urgent research questions, such as defining disease markers and studying mechanisms causing premature neuronal ageing.

The clinical examination will, of course, take place after separate clarification and consent. The in-person examinations will take about one morning, and you can also refuse specific individual tests.