Background: Psychological factors as depression and somatization are considered along with a high level of disability as risk factors for developing persistent low back pain (LBP). Furthermore, LBP and psychosocial distress are two of the most frequent reasons for seeking health care and sickness absence. However, it is not clear how these factors are intercorrelated. The aim of this study was to analyze how pain, fear-avoidance beliefs, depression and somatization were associated with disability in persistent LBP patients.

Methods: In a cross-sectional design, 765 LBP patients filled in Roland Morris Disability Questionnaire, LBP Rating Scale, Fear-Avoidance Beliefs Questionnaire (physical activity/work) and Symptoms Checklist 90 (psychological distress).

Results: In a multivariate regression analysis, disability was found to be significantly associated with pain, depression, fear-avoidance beliefs (physical activity), age and body mass index (BMI). Pain was significantly associated with disability, depression, somatization, sex and BMI. Disability, pain and the psychosocial variables were mutually correlated.

Conclusion: The results of this study support earlier suggestions of an association between disability, pain and the psychosocial factors somatization, depression and fear-avoidance beliefs. The results support the importance of recognizing the mental health of LBP patients in the clinical setting.