1. Institute of Social and Preventive Medicine (ISPM), University of Bern; Bern Switzerland
2. Division of Cancer Epidemiology and Genetics; National Cancer Institute; Bethesda MD
3. Department of Medical Oncology; Inselspital, University Hospital; Bern Switzerland
4. Centre for Infectious Disease Epidemiology & Research, School of Public Health & Family Medicine, University of Cape Town; Cape Town South Africa