Abstract
IMPORTANCE: Physical activity is considered to have both detrimental and beneficial effects on low back pain (LBP). OBJECTIVES: To examine the association of transient (short-term) risk of 10 common physical activities with participant-reported LBP exacerbations (flares) and to estimate cumulative (long-term) risks of each activity with LBP-related functional limitations at 1-year follow-up. DESIGN, SETTING, AND PARTICIPANTS: This prospective, longitudinal case-crossover study nested in a cohort study recruited adults with recent health care visits for LBP at outpatient clinics in Veterans Affairs primary care from March 25, 2021, to September 21, 2023. Participants were followed up for 1 year. EXPOSURES: The number of hours engaged in each activity in the past 24 hours. MAIN OUTCOMES AND MEASURES: Presence of a participant-reported LBP flare (aim 1) and LBP-related functional limitations at 1-year follow-up (aim 2). RESULTS: A total of 416 participants (mean [SD] age, 47.5 [10.9] years; 306 [75%] male) completed 9757 surveys during the 1-year follow-up. Each additional hour in which an activity was performed at least once in that hour was associated with greater risk of subsequent flares for lifting more than 10 lb (odds ratio per hour, 1.05; 95% CI, 1.03-1.07), bending, pushing/pulling, twisting, and squatting. Total duration of sitting was associated with lower risk of flares (odds ratio per additional hour sitting, 0.96; 95% CI, 0.94-0.98). However, the mean hours spent in each activity during the initial 8 weeks of the study was not associated with long-term functional limitations at 1-year follow-up. CONCLUSIONS AND RELEVANCE: This study found short-term, transient risks of LBP flares associated with some activities but no associations with functional limitations at 1-year follow-up. These findings suggest that people with LBP who engage in more of these activities do not have better or worse long-term outcomes.