1. Division of Community Health Sciences, University of Illinois Chicago School of Public Health, Chicago, IL 60612, USA
2. Sweetwaters Centre for Community Based Research, Human Sciences Research Council, Pietermaritzburg 3201, South Africa
3. Medical School, University of Cyprus, Nicosia 1678, Cyprus
4. Department of Hygiene, Epidemiology and Medical Statistics, Medical School, National and Kapodistrian University of Athens, 11528 Athens, Greece
5. Department of Population Health, New York University School of Medicine, New York, NY 10016, USA