Funding
Open Access funding enabled and organized by Projekt DEAL. This study is funded by the German Pension Insurance Berlin-Brandenburg, 15228 Frankfurt (Oder), Germany (grant number: 10-R-40.07.05.07.023). Funding covers personnel, material, and travel costs. The study design, data collection, data analysis, data interpretation and writing of the study protocol are not influenced by the funding body. We acknowledge financial support from the Open Access Publication Fund of Charité – Universitätsmedizin Berlin and the German Research Foundation (DFG).