1. Department of Public Health, Environmental and Social Determinants of Health, World Health Organization , 1211Geneva, Switzerland
2. Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute , 4051Basel, Switzerland
3. University of Basel, 4003Basel, Switzerland
4. Present address: World Health Organization, Geneva, Switzerland
5. Faculty of Health, University of Canberra, ACT2617, Australia