1. Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA
2. The Fenway Institute, Fenway Community Health, Boston, MA, USA
3. Departments of Behavioral & Social Health Sciences and Epidemiology and the Institute for Community Health Promotion, Brown University School of Public Health, Providence, RI, USA
4. Department of Sociomedical Sciences, Columbia University Mailman School of Public Health, New York, NY, USA
5. Department of Biobehavioral Health, Penn State University, University Park, PA, USA
6. Online Buddies, Inc, OLB Research Institute, Cambridge, MA, USA
7. Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
8. Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA, USA