title: No association between ApoE and schizophrenia: Evidence of systematic review and updated meta-analysis.
abstract: BACKGROUND
  Schizophrenia affects between 0.3% and 2% of the worldwide population. A genetic contribution has been postulated in the development of this disorder. Genes such as ApoE have been implicated in the neurodevelopment associated with schizophrenia in case-control and meta-analysis studies, but the results remain inconclusive. Due to this, the aim of the present study was to explore the association between ApoE and schizophrenia through a meta-analysis.
  
  
  METHODS
  We collected all relevant studies by searching PubMed and EBSCO databases. The pooled odds ratios with 95% confidence intervals were calculated to estimate the association. The following models were evaluated: A) ε4 vs ε3, B) ε4 vs ε2, C) ε4 vs ε3+ε2, D) Caucasian population and E) Asian population. Statistical analyses were performed using EPIDAT 3.1 software.
  
  
  RESULTS
  The meta-analyses comprised 28 association studies, which included 4703 controls and 3452 subjects with schizophrenia. A significant protective effect was found for allele ε3 in the Asian population (OR=0.73, 95% CI=0.54-0.98). No significant associations were observed in the other models and populations analyzed.
  
  
  CONCLUSIONS
  Our meta-analysis suggests a protective association between ApoE allele ε3 and schizophrenia in the Asian population.
authors.affiliation: Universidad Juárez Autónoma de Tabasco, División Académica Multidisciplinaria de Jalpa de Méndez, Cunduacán, Tabasco, Mexico. Electronic address: thelma.glez.castro@gmail.com.
authors.forename: Thelma Beatriz
authors.initials: TB
authors.lastname: González-Castro
authors.affiliation: Universidad Juárez Autónoma de Tabasco, División Académica Multidisciplinaria de Comalcalco, Comalcalco, Tabasco, Mexico. Electronic address: alfonso_tovillaz@yahoo.com.mx.
authors.forename: Carlos Alfonso
authors.initials: CA
authors.lastname: Tovilla-Zárate
authors.affiliation: Universidad Juárez Autónoma de Tabasco, División Académica Multidisciplinaria de Jalpa de Méndez, Cunduacán, Tabasco, Mexico. Electronic address: yazmin.hdez.diaz@gmail.com.
authors.forename: Yazmín
authors.initials: Y
authors.lastname: Hernández-Díaz
authors.affiliation: Subdirección de Investigaciones Clínicas, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico, D.F., Mexico. Electronic address: fresan@imp.edu.mx.
authors.forename: Ana
authors.initials: A
authors.lastname: Fresán
authors.affiliation: Universidad Juárez Autónoma de Tabasco, División Académica de Ciencias de la Salud, Villahermosa, Tabasco, Mexico. Electronic address: iselajua22@yahoo.com.mx.
authors.forename: Isela E
authors.initials: IE
authors.lastname: Juárez-Rojop
authors.affiliation: Universidad Juárez Autónoma de Tabasco, División Académica de Ciencias de la Salud, Villahermosa, Tabasco, Mexico. Electronic address: jblecastillo@hotmail.com.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Ble-Castillo
authors.affiliation: Hospital General de Yajalón, Yajalón, Chiapas, Mexico. Electronic address: dralilialonar@yahoo.com.mx.
authors.forename: Lilia
authors.initials: L
authors.lastname: López-Narváez
authors.affiliation: Instituto Nacional de Medicina Genómica (INMEGEN), Servicios de Atención Psiquiátrica (SAP), Secretaría de Salud, México, D.F., Mexico. Electronic address: adgenis@inmegen.gob.mx.
authors.forename: Alma
authors.initials: A
authors.lastname: Genis
authors.affiliation: Universidad Juárez Autónoma de Tabasco, División Académica Multidisciplinaria de Comalcalco, Comalcalco, Tabasco, Mexico. Electronic address: thelma.glezcastro@yahoo.com.mx.
authors.forename: Mervyn Manuel
authors.initials: MM
authors.lastname: Hernández-Alvarado
mesh_terms: D001057:Apolipoproteins E / Q000235:genetics*; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D006801:Humans; D012559:Schizophrenia / Q000235:genetics*
chemical_list: D001057:Apolipoproteins E
keywords: ApoE gene; Meta-analysis; Schizophrenia; Systematic review