Does interview setting influence disclosure of violence? A study in elderly

Background: violence is a very sensitive research topic and interview's setting might influence the participation rate and response accuracy. We aimed to evaluate such effect when assessing the prevalence of different types of violence in a sample of urban elderly by comparing those interviewed at home with those assessed at the research office. Methods: study subjects were members of a cohort of urban dwellers previously assembled using random digit dialling. The initial 450 individuals aged 60-84 years old were invited to participate in the present study, after being randomly allocated into two groups: 150 for being scheduled to research office interview and 300 to home interview. Both groups allocated were similar regarding gender, age, education, marital status and behavioural characteristics such as smoking and drinking alcohol. Information was obtained by face-to-face standardised interviews. Results: we obtained a participation rate of 67.0% in the group allocated to home interview and 70.7% in the other group (P = 0.431). No statistically significant differences were found when prevalence of violence during the previous year was compared according to the interview setting (physical 2.5 versus 1.0%, psychological 19.7 versus 19.0%, financial mistreatment 8.6 versus 9.5%, sexual 1.0 versus 1.0% and neglect 5.1 versus 3.8% in home and research office, respectively). Conclusion: our results indicate that the interview setting has no influence both in participation rate and in the prevalence estimates of different types of violence in the elderly.