Scientific Concept of the National Cohort (status ... - Nationale Kohorte

A.3
A.3 Study design
the participants themselves will not be possible. No oversampling of a specific population
subgroup is planned.
Selection of subjects for the calibration substudy
At recruitment, all Level 2 participants will be asked whether they are willing to take part in a
repeated examination within 12 months (on average 6 months). According to the given sex
and age distribution of the cohort, subjects agreeing to participate in the reassessment will
be consecutively invited for examinations until the required numbers in each stratum and
year (see Table 3.3) are reached.
A.3.1.3 Participation rates
Based on previous experience from population-based studies in Germany, it is estimated
that at least 400,000 primary invitations must be mailed in order to recruit 200,000 subjects
into the cohort, ultimately resulting in a participation proportion of about 50%, following a
multistep invitation and recruitment process (see below). We aim for a high response proportion
in order to obtain a reasonably representative sample of the underlying population.
Measures to achieve high response rates
The high participation proportion rate of 50% will be achieved by employing a comprehensive
contacting and reminder program (see below). We will ensure that population subgroups
with an expected low participation rate (e.g., subjects with a low SES) are well represented
in the cohort by instituting a number of measures. For example, a public relations
representative of the National Cohort responsible for general public relations activities will
provide information on the cohort as a whole. In addition, each study region will authorize a
communication expert who will organize public relations for the recruitment area. The aim
is to implement a number of local public relations activities (adapted to local circumstances)
that raise and maintain awareness of the National Cohort. These may involve:
� Information and integration of local institutions and stakeholders such as local health
authorities, general practitioners, pharmacies, mayors, etc.
� Declaration of support by official representatives of health organizations (e.g., Ministry
of Health, Ministry of Education and Research) and the responsible data privacy
commissioners by letters of support to be mailed with the invitation letters
� Professionally designed information and advertising material (flyer, postcards, posters,
etc.)
� A service telephone and a webpage to provide information on the National Cohort
� Media campaigns including coverage of issues related to the National Cohort in print
media, radio, and television:
– Features and reports in national and local press, radio and television
– Press releases featuring interviews with members of the Epidemiologic Planning
Committee, local principal investigators, local health ministers, and celebrities
– The possibility that national and local reporters and film teams visit the study centers,
create short movie clips, and interview study center staff as well as potential
participants
– Local and national press reports at certain dates (e.g., at the beginning of the
study, halftime, end of baseline recruitment)
� Articles in the national scientific press (e.g., Ärzteblatt)
Furthermore, the promotion campaign will be supported by national and regional organizations
and representatives of medical research and health care systems, such as health insurances
and scientific associations, e.g., the German Epidemiologic Association (DGEpi).
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