Clinical Epidemiology Research Unit, Hospital Infantil de Mexico "Federico Gomez", Mexico City, Mexico. adriana.crpg@ciencias.unam.mx.
Faculty of Medicine of National Autonomous University of Mexico (Universidad, Nacional Autónoma de México), Mexico City, Mexico. adriana.crpg@ciencias.unam.mx.
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA