1 Epidemiology Unit, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid, Avda Reyes Católicos 2, E-28040 Madrid, Spain. Electronic address: [email protected].
2 Epidemiology Unit, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid, Avda Reyes Católicos 2, E-28040 Madrid, Spain.