1. Faculty of Health, Medicine and Life Sciences Maastricht University Maastricht The Netherlands
2. School of Public Health Addis Ababa University Addis Ababa Ethiopia
3. Center for Population Studies Addis Ababa University Addis Ababa Ethiopia
4. School CAPHRI, Care and Public Health Research Institute Maastricht University Maastricht The Netherlands
5. General Practice Research Unit, Department of Community Medicine The Arctic University of Tromsø Tromsø Norway