1. London School of Hygiene and Tropical Medicine; Department of Social and Environmental Health Research; 15 - 17 Tavistock Place London UK WC1H 9SH
2. Lazio Regional Health Service; Department of Epidemiology; Via Cristoforo Colombo, 112 Rome Italy 00154
3. New York University College of Nursing; New York NY USA
4. University of Bristol; School of Social and Community Medicine; Bristol UK
5. UNSW; National Drug and Alcohol Research Centre; Building R3 22-32 King Street Randwick NSW Australia 2031
6. Liverpool John Moores University; Public Health Institute; Liverpool UK L3 2ET
7. Health Protection Scotland; Glasgow UK
8. Kirby Institute, University of New South Wales; Sydney Australia
9. University of West of Scotland; Paisley UK
10. University of Montreal; Department of Family and Emergency Medicine; Montreal Canada