1. Institute for Health Services Research in Dermatology and Nursing, [Center of Excellence for Epidemiology] and Health Services Research for Healthcare Professionals (CVcare), University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany;
2. Department for the Principle of Prevention and Rehabilitation, Institution for Statutory Accident Insurance and Prevention in the Health and Welfare Services, Pappelallee 33/35/37, 22089 Hamburg, Germany