1. Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA
2. Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
3. The Fenway Institute, Fenway Health, Boston, MA, USA
4. Division of Social and Behavioural Health Sciences, University of Toronto, Toronto, Canada
5. Center for Interdisciplinary Research in Sexuality, AIDS and Society, University of Peru Cayetano, Lima, Peru