1. Department of Epidemiology, (Mexican Institute of Social Security Delegation Veracruz Sur), Mexico
2. Department of Medicine of Minatitlán, Universidad Veracruzana (Veracruzana University), Mexico
3. Department of Medicine of Tampico, Universidad Autónoma de Tamaulipas (Autonomous University of Tamaulipas), Mexico
4. Reynosa Aztlán Multidisciplinary Academic Unit, Universidad Autónoma de Tamaulipas, (Autonomous University of Tamaulipas), Mexico