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

A.2 Scientific background and rationale for study elements
risk factor for chronic disease 244, 245 . Thus, most precise measurement of body composition
– and change in body composition during follow-up – is mandatory.
Assessment of body composition:
Examinations (at baseline and during reassessment)
Level 1: Body weight and height
Waist and hip circumference
DXA
MRI program: Whole-body MRI
Physical fitness: Physical fitness refers to a full set of different attributes that people have
or achieve and that relates to the ability to perform physical activity. Among these attributes,
cardiorespiratory fitness, which is the ability of the body‘s circulatory and respiratory systems
to supply oxygen during sustained physical activity, has repeatedly proven to have
an important impact on CHD and other CVD 246 . A recent meta-analysis suggests that cardiorespiratory
fitness and physical activity have significantly different relationships to CVD,
showing reductions in RR nearly twice as great for cardiorespiratory fitness as for physical
activity levels 247 , although physical activity is the most important determinant of cardiorespiratory
fitness. A few prospective cohort studies, so far, have also reported associations
between cardiorespiratory fitness and reduced risk of diabetes. Relationships with risks of
cancers or dementia, however, have not been addressed by well-designed cohort studies.
In addition to cardiorespiratory fitness, measures of reduced muscle strength have been
associated both with increased risks of death from CVD in men and with cancer 248, 249 independently
of other, established risk factors.
Assessment of physical fitness:
Examinations (at baseline and during reassessment)
Level 1: Hand grip strength
Level 2: Step test
One-leg stand / posturometry
Metabolic parameters related to body composition, physical activity, and fitness: The
availability of prediagnostic blood samples in the National Cohort will provide the unique
opportunity to shed light on physiologic mechanisms that may relate excess body weight,
physical inactivity, and reduced physical fitness to risks of CVD, cancer, and mortality by
measuring biomarkers from pertinent pathways 250-252 .
Prior studies have shown, for example, that obesity-related markers such as adiponectin,
C-reactive protein, or resistin predict risk of CVD beyond established risk factors (including
anthropometric measures of adiposity and fat distribution) and that a substantial proportion
of CVD incidence may be accounted for by such factors 253 . Other adiposity-related metabolic
alterations, such as hyperinsulinemia, increases in bioavailable sex steroids (androgens
and estrogens), and chronic low-grade inflammation, have been related to risks of
developing tumors of the colorectum and breast, for example. Further metabolic factors that
have been studied in this context include indicators of glucose tolerance, blood lipid profile,
and serum levels of specific growth factors, coagulation factors, inflammation factors, or
changes in immune function. The advances in science and technology over the past few
years, especially the development of high-throughput laboratory methods, offer the opportunity
to identify novel biomarkers for cardiovascular risk factors using discovery-oriented
approaches (e.g., metabolomics, proteomics).
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A.2