1 Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece.
2 Faculty of Medicine, Department of Surgery & Cancer, IRDB, Imperial College, London, UK; Department of Obstetrics and Gynaecology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
3 Faculty of Medicine, Department of Surgery & Cancer, IRDB, Imperial College, London, UK; West London Gynaecological Cancer Center, Queen Charlotte's & Chelsea - Hammersmith Hospital, Imperial Healthcare NHS Trust, London.
4 Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece; Department of Epidemiology, Biostatistics School of Public Health, Imperial College London, London, UK. Electronic address: ktsilidi@cc.uoi.gr.