Background and purpose: Low back pain is common among Brazilians, especially affecting those who are working. Psychosocial factors, such as the health locus of control, are associated with low back pain prognoses. Although the multidimensional health locus of control questionnaire is widely employed in individuals with low back pain, a Brazilian-Portuguese version is not yet available. The aim of the present study was to translate and adapt the multidimensional health locus of control (MHLC) questionnaire, and to investigate its psychometric properties in a Brazilian population with non-specific chronic low back pain.
Method: Translation and adaptation of the questionnaire was carried out in the first phase of the study. In the second phase it was administered to Brazilians with non-specific chronic low back pain to evaluate its intra-examiner reliability (n=20), concurrent validity, internal consistency (n=40), and floor and ceiling effects. To evaluate concurrent validity the Brazilian-Portuguese version of the Roland-Morris disability questionnaire was used as the comparison.
Results: The sub-scales demonstrated good to excellent reliability with intra-class coefficient (ICC) values of 0.75 for the external subscale (95% confidence interval (95% CI): 0.46-0.89), 0.87 for the internal sub-scale (95% CI: 0.69-0.94) and 0.90 for the chance sub-scale (95% CI: 0.77-0.96). For concurrent validity, the external and chance sub-scales correlated positively with disability (Pearson's r=0.58; p<0.001 and Pearson's r=0.35; p=0.025), respectively, while the internal sub-scale correlated negatively with disability (Pearson's r= -0.33; p=0.037). The questionnaire had acceptable internal consistency, with a Cronbach's alpha value of 0.65 (95% CI: 0.46-0.80) for external sub-scale, 0.77 (95% CI: 0.64-0.87) for internal sub-scale and 0.83 (95% CI: 0.73-0.90) for chance sub-scale.
Conclusions: The Brazilian-Portuguese version of the MHLC questionnaire has acceptable measurement properties similar to that observed with the original English language version.