The German National Cohort (NAKO): Current state and further follow-up data collection

Abstract The German National Cohort (NAKO) is a multidisciplinary, population-based cohort study that aims to investigate the development and aetiology of diseases, identify risk factors and enhance early detection and prevention of diseases. Between 2014 and 2019, a total of 205,415 subjects aged 20 -74 years were recruited and examined at 18 study centres across Germany. The baseline assessment included a face-to-face interview, self-administered questionnaires, a wide range of biomedical examinations and the collection of various bio samples. Furthermore, whole-body magnetic resonance imaging (MRI) was performed on 30,861 participants at 5 of the18 study centres. The first re-examination of study participants started in October 2018, and will be completed end of July 2024 aiming for at least 135, 000 participants. Until April 2024 134,428 participants completed their second examination, including 18,707 participants with additional MRI examination. The second re-examination will start in May 2024 and will last until April 2028 aiming to examine at least 85,000 participants for a third time. Besides the examinations at the study centres, participants receive written health questionnaires (GEFUs) 2-3 years after their last examination to get additional information on incident diseases and changes in exposures. The first GEFU questionnaire (GEFU-1) was conducted between October 2017 and May 2023 and was filled in by 171,181 participants. Since the start of GEFU-2 in March 2023 65,624 participants have answered the GEFU-2 questionnaire. Due to the longitudinal design, the large sample size and the broad examination programme, NAKO provides information on determinants of population health and disease. Thus, it is a valuable resource for researchers from different disciplines.