1. Morbid Obesity Centre, Vestfold Hospital Trust, Tønsberg, Norway
2. Department of Surgery, Vestfold Hospital Trust, Tønsberg, Norway
3. Department of Laboratory Medicine, Vestfold Hospital Trust, Tønsberg, Norway
4. Department of Endocrinology, Morbid Obesity and Preventive Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway