Reliability and validity of the Persian version of the Falls Efficacy Scale-International.

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To the Editor: With the increase in life expectancy, the number of adults aged 60 and older will increase to 2 billion by 2050, 80% of whom will be living in developing countries.1 Falling is one of the main health problems of older adults, with approximately one-third of individuals aged 65 and older experiencing falls.2 Falls and fear of falls are related to one another, with each being a risk factor for the other.3 Fear of falls may result in avoidance of daily activities and reduction in the older adult's quality of life.4, 5 The Falls Efficacy Scale—International (FES-I) is an instrument that Prevention of Falls Network Europe (ProFaNE) designed to investigate fear of falls in older adults.6 The present study was conducted to assess the reliability and validity of a Persian version of the FES-I in Iranian older adults. Individuals aged 60 and older from a retirement center in Tabriz (Iran) who were able to speak, comprehend, read, and write Persian and were living independently in the community participated (n = 200). The study was performed between October 2012 and March 2013 after approval of the ethics committee of Tabriz University of Medical Sciences. The FES-I is a self-report questionnaire with 16 items assessed on a four-item Likert scale (not at all concerned to very concerned).6 Cronbach alpha (internal consistency) and Spearman-Brown correlation coefficients (test–retest) were used to investigate reliability; values greater than 0.7 indicated good reliability, and values less than 0.5 indicated unacceptable reliability.7 To determine the validity of the construct, exploratory and confirmatory factor analysis were considered. Correlation matrix, principal axis factoring, varimax rotation, and the Kaiser-Meyer-Olkin measure of sampling adequacy (KMO) were used for exploratory factor analysis.1 To evaluate the structure of the factors of exploratory factor analysis, goodness of fit of confirmatory factor analysis was conducted based on chi-square degrees of freedom (χ2/df) less than 5, goodness-of fit index (GFI), adjusted goodness-of-fit index (AGFI) greater than 0.9, root mean square residual (RMSR) less than 0.1, root mean square error of approximation (RMSEA) less than 0.08, comparative fit index (CFI) greater than 0.9, normed fit index (NFI) greater than 0.9, non-normed fit index (NNFI) greater than 0.9, incremental fit index (IFI) greater than 0.9, relative fit index (RFI).7 Data analysis was performed using SPSS version 11.5 (SPSS Inc., Chicago, IL). In all analyses, P < .05 was considered statistically significant. Cronbach alpha was 0.90 to 0.95 and Spearman-Brown correlation coefficients were 0.82 to 0.84 for the factors and total instrument. The adequacy of the factor analysis model was confirmed (KMO = 0.936 and for Bartlett test, χ2 of Bartlett test was 2,505.781, df 120, P < .05). In exploratory factor analysis with varimax rotation, two factors were extracted. Items 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, and 16 from the questionnaire were loaded in the first factor, and items 11, 13, 14, and 15 were loaded in the second factor. Two extracted factors determined 67.55% of total variance changes.1 In confirmatory factor analysis, based on the comparison of the data of goodness of fit for two- and one-factor analysis and theoretical basic (χ2/df < 5, RMSR < 0.1, NFI > 0.9, NNFI > 0.9, CFI > 0.9, IFI > 0.91) and the closeness of GFI and AGFI to 0.9, there was no considerable difference in these values for three models. All relationships between the items and factors were significant (P < .05). Thus, based on this model, the structure of exploratory factor analysis for this questionnaire was confirmed in two factors (Table 1). Test–retest and internal consistency reliability in accordance with previous literature were confirmed.6, 8-10 In the investigation of factor analysis in the present study and other studies, two factors were extracted, but loaded items on each factor in the studies were different.6, 10 Based on the results of this study, the Persian version of the FES-I has good validity and reliability in community-dwelling older people. This instrument can be used as an easy, low-cost method of measuring fear of falling in Iranian older adults. This article is the result of a thesis approved by the ethics committee of Tabriz University of medical sciences no. 9161. Our gratitude goes to all the older adults participating in this study, ProFANE, and the collaboration of Persian and English translators who helped us in translating the instrument. Finally, we are grateful to the staff of the Tabriz retirement center in allowing us to conduct the research there. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: All authors contributed to this paper. Sponsor's Role: None.