1 Department of Epidemiology, Harvard T.H. Chan School of Public Health. Boston, United States. maflores@hsph.harvard.edu.
2 Center for Research on Population Health, National Institute of Public Health. Mexico City, Mexico. rodrigo.huerta.gdv@gmail.com.
3 Department of Family and Community Medicine, University of California, San Francisco School of Medicine. San Francisco, United States. Michael.Potter@ucsf.edu.