Data collection

For the GeoLynch study we are interested in the dietary habits and lifestyle of persons with Lynch syndrome. We collect this information through questionnaires, which are filled out by the participants at home. Participants are asked to fill out three questionnaires:

1. a general questionnaire about health, family and lifestyle habits,
2. a questionnaire about dietary habits,
3. a questionnaire about any use of dietary supplements.
   

We also would like to determine the waist and hip circumference to get an indication of abdominal fat. In the general questionnaire participants are asked to write down their waist and hip circumference. The waist and hip circumference are measured by the participant with a tape measure, which has been included with the questionnaire.

After the GeoLynch participants have filled out the questionnaires we ask them to donate a blood sample. Blood sampling is carried out in cooperation with SHO Centres for Medical Diagnostics. Date and time for blood sampling is scheduled in consultation with the participant. We aim to use local polyclinics so that participants will not have to travel far. If the policlinic is too far away from a participants home, the SHO can plan an appointment for blood sampling at home. Participants do not have to fast before the blood sampling. For the blood sampling five small tubes of blood are collected, which will only take 5 to 10 minutes.

The blood samples will be analysed to determine concentrations of nutrients that may affect the development of tumours. Besides, the researchers will investigate the natural variation in DNA and the risk of developing tumours. For example, they will look at the effect of natural variation in DNA on the metabolism of nutrients in the body.

In order to store the blood for these analyses it has to be processed immediately. The blood samples are stored in a -80 ⁰C freezer until all the blood samples from all participants in the GeoLynch study have been collected. In this way all blood samples can be analysed at the laboratory at the same time.

The storage of blood for scientific research such as the GeoLynch study, is called a biobank. The definition of a biobank is: "a collection of biological samples and sometimes information about patients and/or healthy volunteers, which can be used for biomedical research." You can find general information about biobanking in the Netherlands at www.biobanken.nl.