Internationale Kohortenstudien

Abstract

Among observational studies, cohort studies, i.e. longitudinal observations of selected population groups, provide the highest possible evidence of a causal association between specific risk factors (exposure) and the occurrence of disease in populations. Besides the fact that many exposures cannot be investigated in experimental designs, cohort studies have the advantage over randomized clinical trials that they are conducted in free living populations and not in restrictive, clinical settings. In this paper we describe the aims and features of international cohorts that have been selected because of their impact, their size or their endpoints. We do not only present the study designs and survey instruments used but we also highlight some of the most important results gained by these studies. Most of these prospective studies investigated common chronic diseases in the elderly, such as cancer, diabetes, cardiovascular or neurodegenerative diseases, osteoporosis and ophthalmologic disorders. Newer cohorts and recent reassessments of existing cohorts almost always include the collection and storage of biological samples. In recent years technological developments allowed the implementation of cutting edge measurement procedures, such as imaging techniques for phenotyping. Finally, we discuss on the one hand whether these designs can be transferred to the German situation and on the other hand to what degree the results obtained from foreign cohorts can be generalized for the German population. We conclude with recommendations for future cohort studies.