1Bone and Mineral Research Unit, Hospital Universitario Central de Asturias, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Universidad de Oviedo, Retic REDinREN-ISCIII, Avda. Roma, sn., 33011 Oviedo, Spain
2Nephrology Department, Centro Hospitalar e Universitário de Lisboa Central, Nova Medical School, Nova University, Lisbon, Portugal