[1] Pontificia Univ Catolica Chile, Dept Pediat, Fac Med, Santiago, Chile
[2] Pontificia Univ Catolica Chile, Dept Enfermedades Cardiovasc, Fac Med, Santiago, Chile
[3] Pontificia Univ Catolica Chile, Dept Salud Publ, Fac Med, Santiago, Chile
[4] Pontificia Univ Catolica Chile, Programa Magister Estadist, Santiago, Chile