1. Universitaetsklinikum Duesseldorf, Heinrich-Heine University; Department of General Practice; PO Box 101007 Duesseldorf Germany 40001
2. Cochrane Metabolic and Endocrine Disorders Group; Researcher in Systematic Reviews ; Hasenheide 67 Berlin Germany 10967
3. Institute for Quality and Efficiency in Health Care; Dillenburger Str. 27 Cologne Germany 51105