1 Center for Population Health Research, National Institute of Public Health, Mexico, Av. Universidad 655, 62100, Cuernavaca, Mexico.
2 Gerarld J. and Dorothy R. Friedman School of Nutrition Science and Policy, Tufts University, 150 Harrison Ave, Boston, MA, 02111, USA.
3 Center for Population Health Research, National Institute of Public Health, Mexico, Av. Universidad 655, 62100, Cuernavaca, Mexico. tbarrientos@insp.mx.