1 Department of Gastrosurgical Research, Institute of Clinical Sciences, Gothenburg University, Gothenburg, Sweden.
2 Welsh Institute of Metabolic and Bariatric Surgery, Swansea Bay University Health Board, Swansea, UK.
3 Department of Gastrosurgical Research, Institute of Clinical Sciences, Gothenburg University, Gothenburg, Sweden. torsten.olbers@liu.se.
4 Institute for Clinical and Experimental Medicine, Linköping University and Department of Surgery, Vrinnevi hospital, Norrköping, Sweden. torsten.olbers@liu.se.