Transient physical and psychosocial activities increase the risk of nonpersistent and persistent low back pain: a case-crossover study with 12 months follow-up.

BACKGROUND CONTEXT: A previous study has shown that transient physical and psychosocial activities increased the risk of developing low back pain. However, the link between these factors in triggering nonpersistent or persistent episodes remains unclear.

PURPOSE: We aimed to investigate the association of transient exposures to physical and psychosocial activities with the development of nonpersistent or persistent low back pain.

STUDY DESIGN: This was a case-crossover study with 12 months follow-up.

PATIENT SAMPLE: We included 999 consecutive participants seeking care for a sudden onset of low back pain.

OUTCOME MEASURES: Development of low back pain was the outcome measure.

MATERIALS AND METHODS: At baseline, participants reported transient exposures to 12 predefined activities over the 4 days preceding pain onset. After 12 months, participants were asked whether they had recovered and the date of recovery. Exposures in the 2-hour period preceding pain onset (case window) were compared with the 2-hour period, 24 hours before pain onset (control window) in a case-crossover design for all participants. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CI), and interaction analyses were used to compare estimates of nonpersistent (i.e., <6 weeks duration) and persistent cases. This study received funding from Australia's National Health and Medical Research Council (APP1003608).

RESULTS: There were 832 participants (83%) who completed the 12 months follow-up successfully. Of these, 430 participants had nonpersistent low back pain (<6 weeks duration), whereas 352 reported persistent symptoms (≥6 weeks duration). Exposure to several transient activities, such as manual tasks involving heavy loads, awkward postures, live people or animals, moderate or vigorous physical activity, and being fatigued or tired during a task or activity, significantly increased the risk of both nonpersistent and persistent low back pain, with ORs ranging from 2.9 to 11.7. Overall, the risk of developing a persistent or a nonpersistent episode of low back pain associated with the included physical factors did not differ significantly.

CONCLUSIONS: Our results revealed that previously identified triggers contribute equally to the development of both nonpersistent and persistent low back pain. Future prevention strategies should focus on controlling exposure to these triggers as they have the potential to decrease the burden associated with both acute and chronic low back pain.