1. Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
2. Surgery Department, São João University Medical Center, 4200-319 Porto, Portugal
3. Obesity Integrated Responsibility Unit (CRI-O), São João University Medical Center, 4200-319 Porto, Portugal
4. MEDCIDS—Department of Community Medicine, Information and Health Decision Sciences, Faculty of Medicine, University of Porto, 4200-450 Porto, Portugal
5. CINTESIS—Center for Health Technology and Services Research, 4200-450 Porto, Portugal