Daily spinal mechanical loading as a risk factor for acute non-specific low back pain: a case-control study using the 24-Hour Schedule.

A case-control study was conducted to assess the daily loading of the spine as a risk factor for acute non-specific low back pain (acute LBP). Acute LBP is a benign, self-limiting disease, with a recovery rate of 80-90% within 6 weeks irrespective of the treatment type. Unfortunately, recurrence rates are high. Therefore, prevention of acute LBP could be beneficial. The 24-Hour Schedule (24HS) is a questionnaire developed to quantify physical spinal loading, which is regarded as a potential and modifiable risk factor for acute and recurrent low back pain. A total of 100 cases with acute LBP and 100 controls from a primary care setting were included. Cases and controls completed questionnaires regarding acute LBP status and potential risk factors. Trained examiners blinded to subjects' disease status (acute LBP or not) assessed spinal loading using the 24HS. The mean difference of 24HS sum-scores between groups was statistically significant (P < 0.0001). After multivariate regression analysis, previous episode(s), the 24HS and the Nottingham Health Profile were associated with the presence of acute LBP. High 24HS scores, indicating longer and more intensive spinal loading in flexed position, are strongly associated with acute LBP.