Background and purpose: Local languages enhance the comprehensibility of scales as cultural groups’ disease expressions, and their use in various health care systems differs [1]. This study aimed to translate, culturally adapt and conduct a psychometric evaluation of the Yoruba version of the Back Beliefs Questionnaire (BBQ).

Relevance: This study has helped to establish the psychometric properties (validity and reliability) of the BBQ-Y, and also added to the existing literature on the translation of the BBQ.

Methods: The English version of the BBQ [2] was translated into the Yoruba language through a process of forward-backward translation, reconciliation and harmonization of the reconciled items sequentially [1]. Thereafter, the translated Yoruba BBQ (BBQ-Y) was subjected to psychometric evaluation in a cross-sectional study conducted among 119 patients (56.3% females) with chronic low-back pain. However, only 51 of the patients were involved in the reliability testing of the BBQ-Y. The reliability of the BBQ-Y was evaluated using the intra-class correlation (ICC), Bland-Altman plot, standard error of measurement (SEM) and the minimal detectable change (MDC). The internal consistency of the BBQ-Y was determined using Cronbach’s alpha. Using Spearman ranks correlation analysis, the concurrent validity of the FABQ-Y with pain intensity (VAS) was carried out. The authors determined the factor structure of the BBQ-Y using Principal Factor Analysis (PFA) with Oblimin rotation.

Analysis: Data were analysed using descriptive and inferential statistics. Alpha level was set at α=0.05.

Results: The mean age, weight, height, and body mass index were 56.8±8.5years, 69.0±9.4Kg, 1.6±0.1m, and 25.9±3.8kg/m2 respectively. The global score α and ICC of the BBQ-Y was 0.71 and 0.89 respectively. Bland-Altman analysis showed limits of agreements of -6.84 and 5.70 for the test-retest reliability of the BBQ-Y. The standard error of measurement and minimum detectable change of the BBQ-Y was FABQ was 2.3 and 6.4. Factor analysis of the BBQ-Y yielded three factors (Factor 1: Items- 2, 3, 6-8, 10, 14; Factor 2: 1, 4, 5, 13 and Factor 3: Items - 9, 11, 12)  which accounted for 45% of the variance.  Only six of the scoring items identified by the developers of the BBQ loaded into the same factor in the BBQ-Y. The BBQ-Y poorly correlated (r = 0.273, p = 0.001) with the VAS.

Conclusion: The Yoruba language translation of the back beliefs questionnaire has adequate psychometric properties.

Implication: Owing to the acceptable psychometric properties of the BBQ-Y, it recommended as an appropriate outcome measure tool for clinical use among the Yoruba speaking patients with low back pain.

Funding Source: No funding was received for this study.

Ethics approval: The Health Research and Ethics Committee of the Institute of Public Health, College of Health Sciences Obafemi Awolowo University, Ile-Ife gave approval for this study.

Keywords: Back beliefs questionnaire; low back pain; psychometric evaluation; translation