1. Upper Gastrointestinal Surgery, Department of Molecular medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden;
2. Surgical Care Science, Department of Molecular medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden;
3. Demography Unit, Department of Sociology, Stockholm University, Stockholm, Sweden;
4. School of Cancer and Pharmaceutical Sciences, King’s College London, London, UK