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

A.1
A.1 Introduction and overview
spective cohorts we can examine, using the existing biobank resources, whether a given
biomarker (or combination of markers) can predict disease occurrence ahead of its “natural”
date of diagnosis (estimation of “lead time“).
To guarantee a high quality of phenotyping at the molecular level for future studies, a comprehensive
array of biomaterials must be available in optimal quality. To achieve this, preanalytical
artifacts that could incur during specimen collection, primary processing, transport,
and storage of the samples need to be minimized. Therefore, all particular components of
full blood must be promptly and completely separated, ideally within 1 h of collection, there
should be no delay in preparing and freezing aliquots, and volumes should be small to guarantee
single use as opposed to repeat thaw-freeze cycles. The high quality of the National
Cohort Biobank will be assured by processing the biomaterials locally, not centrally, in a
highly standardized manner and automating all steps in preparation, storage, and retrieval
of stored materials. For details, see Sect. A.3.5.
A.1.5 Arguments for a large cohort in Germany
Several smaller prospective cohort studies already exist in Germany, and in other European
countries several large-scale prospective cohorts are currently being set up or have been
implemented. It thus may be useful to explain the rationale for planning a new, large cohort
study in this country.
Added value in comparison to existing German cohorts
Several medium-sized epidemiologic cohort studies are currently ongoing in Germany, covering
a total of 100,000–120,000 individuals (see Sect. A.3.9). Not all of these are representative
for the general population, however. Many of the studies were planned independently
of each other and have different study elements. Thus, only for some of the existing German
cohorts could pooled data analyses be conducted, and then for only part of the data collected,
addressing rather basic research questions.
� One first added value of the National Cohort in comparison to existing German cohorts
is that it will have a homogeneous study protocol for a very large sample size;
thus, research questions can be addressed for which existing German cohorts are
statistically underpowered.
� The participants in most existing cohorts in Germany already have a median age
above 50 years (in some of the larger cohorts [e.g., EPIC] even above 60 years) and
cannot be used to study the early development of disease.
� The existing cohorts were initiated up to 25 years ago and the requirements for exposure
assessment, including blood sample ascertainment, are now new.
� The National Cohort will provide a population-representative, highly standardized,
comprehensive database that covers much of the heterogeneity both with respect to
risk factors and major diseases in all of Germany.
Added value of the National Cohort in comparison to other European cohorts
Several large epidemiologic cohort studies exist or are being planned in other European
countries (e.g., the UK, Netherlands, France, Sweden). As summarized in more detail in
Sect. A.3.9 and Tables 3.16 and 3.17, the National Cohort will have several advantageous
characteristics as compared with other large European cohorts:
� High quality of biosamples by highly standardized preanalytical processing and automated
storage
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