The German National Cohort (NAKO) aims to gain insights into how common and, in particular, chronic diseases in Germany are linked to nutritional behaviour. To this end, NAKO participants receive questionnaires from their study centre.
- Each participant can decide for themselves whether they would like to complete the nutrition survey online or on paper. The study centres will issue individual login details for the online survey. Those who opt for the paper version will receive the questionnaires together with prepaid envelopes on the day of the survey. These are simply sent back to the centres by post.
- The short questionnaires on the previous day’s diet are completed four times at three-month intervals. It is important that the answers actually relate to the four days that were communicated to the participant by telephone or letter. This is the only way to ensure random selection.
- It takes about 10 to 20 minutes to complete a short questionnaire.
- The more extensive questionnaire on nutrition in the last year (FFQ) is more comprehensive and takes about 30 to 40 minutes to complete, depending on individual nutritional behaviour.
Short questionnaire on nutrition the day before
Over the course of the study, the NAKO participants complete a total of four questionnaires about their diet on the previous day. There is an interval of around three months between the individual questionnaires so that the seasonal effects of the diet can also be taken into account. The questionnaire specifies food groups that are frequently consumed in Germany. From these, the participants choose which foods they ate the day before.
Questionnaire on nutrition over the past twelve months (FFQ)
Participants are also given another questionnaire to assess how often they have eaten certain foods in the past year. From a given list of foods and the approximate portion size, they can assess the frequency using a scale. This also records foods that are rarely eaten, for example, and are therefore not mentioned in the short questionnaire. Following the survey at the study centre, participants receive the FFQ to complete at home.
