Psychometric properties of the Japanese version of the Fear-Avoidance Beliefs Questionnaire (FABQ).

BACKGROUND: The Fear-Avoidance Beliefs Questionnaire (FABQ) is useful for measuring fear-avoidance beliefs in patients with low back pain (LBP); however, no psychometrically validated Japanese version is available. The objective of this study was to evaluate reliability and validity of the Japanese version of the FABQ for use with Japanese workers with LBP. METHODS: This was conducted as a web-based survey. Both confirmatory and exploratory factor analysis were performed to examine domain structure of the Japanese version of the FABQ. For reliability, internal consistency was assessed with Cronbach's alpha coefficient. For concurrent validity, correlation coefficients between the FABQ and the Pain Catastrophizing Scale (PCS) were calculated. For known-group validity, the relationship between FABQ score and clinical variables such as pain and depression was examined. RESULTS: Analyses were based on responses of 1,786 adult Japanese workers with LBP. Factor analysis using the principal factor method with promax rotation revealed two factors, work and physical activity, in accordance with the domain structure of the original version of the scale. For reliability, acceptable internal consistency was demonstrated with Cronbach's alpha coefficient of 0.882 and 0.783 for each subscale. For concurrent validity, significantly moderate correlations were demonstrated between FABQ subscales and PCS subscales (r = 0.30-0.39). For known-group validity, as hypothesized, significantly higher FABQ subscale scores were observed in workers who had stronger pain, who experienced routine work disability with sick leave, who experienced recurrence of LBP, and who had depressed mood. CONCLUSIONS: This analysis showed that the Japanese version of the FABQ is psychometrically reliable and valid to detect fear-avoidance beliefs in Japanese workers with LBP.