1. University Medical Center Utrecht; Julius Center for Health Sciences and Primary Care; Universiteitsweg 100 Utrecht Netherlands 3508 GA
2. Faculty of Medicine and Health Sciences, Universiti Putra Malaysia; Department of Family Medicine; Serdang Selangor Malaysia 43400 UPM
3. Institute of General Practice, Medical Faculty of the Heinrich-Heine-University Düsseldorf; Cochrane Metabolic and Endocrine Disorders Group; Moorenstr. 5 Düsseldorf Germany 40225
4. Julius Center for Health Sciences and Primary Care / University Medical Center Utrecht; Cochrane Netherlands; Room Str. 6.126 P.O. Box 85500 Utrecht Netherlands 3508 GA