title: Confirmatory factor analysis of the WHO Violence Against Women instrument in pregnant women: results from the BRISA prenatal cohort.
abstract: BACKGROUND
  Screening for violence during pregnancy is one of the strategies for the prevention of abuse against women. Since violence is difficult to measure, it is necessary to validate questionnaires that can provide a good measure of the phenomenon. The present study analyzed the psychometric properties of the World Health Organization Violence Against Women (WHO VAW) instrument for the measurement of violence against pregnant women.
  
  
  METHODS
  Data from the Brazilian Ribeirão Preto and São Luís birth cohort studies (BRISA) were used. The sample consisted of 1,446 pregnant women from São Luís and 1,378 from Ribeirão Preto, interviewed in 2010 and 2011. Thirteen variables were selected from a self-applied questionnaire. Confirmatory factor analysis was used to investigate whether violence is a uni-or-multidimensional construct consisting of psychological, physical and sexual dimensions. The mean-and-variance-adjusted weighted least squares estimator was used. Models were fitted separately for each city and a third model combining data from the two settings was also tested. Models suggested from modification indices were tested to determine whether changes in the WHO VAW model would produce a better fit.
  
  
  RESULTS
  The unidimensional model did not show good fit (Root mean square error of approximation [RMSEA]  = 0.060, p < 0.001 for the combined model). The multidimensional WHO VAW model showed good fit (RMSEA = 0.036, p = 0.999 for the combined model) and standardized factor loadings higher than 0.70, except for the sexual dimension for SL (0.65). The models suggested by the modification indices with cross loadings measuring simultaneously physical and psychological violence showed a significantly better fit compared to the original WHO model (p < 0.001 for the difference between the model chi-squares).
  
  
  CONCLUSIONS
  Violence is a multidimensional second-order construct consisting of psychological, physical and sexual dimensions. The WHO VAW model and the modified models are suitable for measuring violence against pregnant women.
authors.affiliation: Department of Medicine III, Federal University of Maranhao, Sao Luis, Brazil.
authors.forename: Marizélia Rodrigues Costa
authors.initials: MR
authors.lastname: Ribeiro
authors.affiliation: Department of Public Health, Federal University of Maranhao, Sao Luis, Brazil.
authors.forename: Maria Teresa Seabra Soares
authors.initials: MT
authors.lastname: de Britto e Alves
authors.affiliation: Department of Public Health, Federal University of Maranhao, Sao Luis, Brazil.
authors.forename: Rosângela Fernandes Lucena
authors.initials: RF
authors.lastname: Batista
authors.affiliation: Department of Odontology, Federal University of Maranhao, Sao Luis, Brazil.
authors.forename: Cecília Cláudia Costa
authors.initials: CC
authors.lastname: Ribeiro
authors.affiliation: Department of Preventive Medicine, Faculty of Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Lilia Blima
authors.initials: LB
authors.lastname: Schraiber
authors.affiliation: Department of Pediatrics, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Brazil.
authors.forename: Marco Antônio
authors.initials: MA
authors.lastname: Barbieri
authors.affiliation: Department of Pediatrics, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Brazil.
authors.forename: Heloisa
authors.initials: H
authors.lastname: Bettiol
authors.affiliation: Department of Public Health, Federal University of Maranhao, Sao Luis, Brazil.
authors.forename: Antônio Augusto Moura
authors.initials: AA
authors.lastname: da Silva
mesh_terms: D015331:Cohort Studies; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008962:Models, Theoretical; D011247:Pregnancy; D012742:Sex Offenses; D013312:Stress, Physiological; D013315:Stress, Psychological; D011795:Surveys and Questionnaires; D014754:Violence; D014944:World Health Organization