Skip to main content


Aim of the “IDEFICS/I.Family follow-up study – lifestyle and health”

From 2007 to 2016 more than 16,000 participants from 9 European countries participated in the IDEFICS/I.Family study. Also you contributed to these large studies and provided important insights for health research. Now we invite you again to take part in this follow-up study. The aim of the study is to find out whether your lifestyle has changed in the past years and if the lifestyle might have had an impact on your well-being, health and risk of disease. From our previous studies we already know that lifestyle habits e.g. physical activity or dietary behaviour influence children’s and adolescent’s health. Meanwhile, the participants of the IDEFICS/ I.Family studies are adolescents or adults and enter in a new phase of life.

For many young people, this means moving to another school or starting an apprenticeship. It is also a time when young people develop their own lifestyle that can affect their future health.

We want to further explore the health and lifestyle of young people who have participated in the IDEFICS/I.Family studies. What has changed in recent years? How do you live? How healthy are you? Answering these questions helps us to understand how lifestyle changes from childhood to young adulthood affect health and how to prevent certain diseases.

Please read this study information and the consent form carefully and ask your parents for help if there is anything you do not understand.

What do we ask you to do when you participate?

The study consists of a questionnaire. We ask what you eat, how you sleep, how often you are physically active, how you feel, if you were ill and if you had to take medication. We also ask you about your height and your weight. Answering the questions takes about 45 minutes. You can complete the questionnaire online (via the study website) or as a paper version.

Are there any benefits in participating?

You will remain part of our large IDEFICS/ I.Family community and we will keep you informed about the most important research results. If you wish, we will give you hints on where to stand with your personal habits and where you might be able to improve.

But most of all, you and your child make an important contribution to improving the health of young people and developing specific measures to prevent diseases. But above all, you make an important contribution to improving the health of young people and developing targeted disease prevention measures.

How are the collected data protected?

All collected study data are stored at Leibniz Institute for Prevention Research and Epidemiology – BIPS in Bremen. The questionnaire information will be kept separate from your name and address in a safe and secure place. Neither your parents, nor teachers, nor anyone else will know anything about your answers. These data are marked with an identification number, the so-called "ID number". Only this ID number is used for the scientific evaluation of all questionnaires. Your name and contact details will not be mentioned or published in any report.  

We comply with all data protection laws! If you have questions about data protection, you will find the responsible contact persons at the end of this study information. Please speak to your parents before calling someone from this list.

Participation in the study and possibility of withdrawal

Your parents have given their permission for your participation in this online survey. Now we kindly ask you to support us by registering. Then you will receive an e-mail with a link to the questionnaire.

Participation in this study is voluntary. There are no disadvantages for you or your family if you do not participate. You can change your decision at any time and cancel your participation. You don't have to give a reason for this. It is sufficient if you or your parents inform us in writing or verbally.

If you have any questions about the study, please feel free to contact us:

I.Family study

Project coordinator
Professor Dr Wolfgang Ahrens

Leibniz Institute for Prevention Research and Epidemiology - BIPS 
Dept. Epidemiological Methods and Etiological Research 
Achterstrasse 30, 28359 Bremen, Germany