1. Institute for Complementary and Integrative Medicine, University Hospital Zurich and University of Zurich, Zurich, Switzerland
2. Department of Biostatistics at the Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland
3. Department of Mathematical Sciences, Norwegian University of Science and Technology, Trondheim, Norway
4. Institute of Primary Care, University Hospital Zurich, Zurich, Switzerland
5. Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Social Medicine, Epidemiology and Health Economics, Berlin, Germany
6. Center for Integrative Medicine, University of Maryland, School of Medicine, Baltimore