RESUMO
BACKGROUND: Analgesics are the most common form of managing low back pain (LBP). No previous study has examined which domains and intensities of physical activity are most beneficial in reducing the frequency of analgesic use for LBP and its related activity limitation. METHODS: This cohort study forms part of the AUstralian Twin low BACK pain study, investigating the impact of physical activity on LBP. Information on demographics, LBP and health-related factors, including physical activity, were collected at baseline. Data on the total counts of analgesic use and activity limitation for LBP were collected weekly for one-year. Negative binomial regression models were conducted separately for each type of physical activity. Results were presented as incidence rate ratios (IRRs) and 95% confidence intervals (CIs). RESULTS: From an initial sample of 366 participants, 86 participants reported counts of analgesic use and 140 recorded counts of activity limitation across the follow-up period. The negative binomial regression models for analgesic use counts indicated that engagement in moderate-vigorous physical activity was protective for use of analgesics (IRR 0.97, 95% CI 0.96-0.99), while physical workload was associated with greater use (IRR 1.02, 95% CI 1.01-1.05). No other significant relationships were observed for the other measures of physical activity. For activity limitation counts, engagement in leisure activity was associated with less counts of activity limitation (IRR 0.94, 95% CI 0.81-0.99), while greater amounts of sedentary time was associated with higher counts (IRR 1.04, 95% CI 1.01-1.09). No other significant relationships were observed for the other measures of physical activity. CONCLUSIONS: Our findings highlight the potential importance of supporting engagement in moderate-vigorous and leisure physical activity as well as minimizing sedentary time and physical workload to reduce the risk of activity limitation and the need for analgesic use in people with LBP. SIGNIFICANCE: We examined which domains and intensities of physical activity are most beneficial in reducing the frequency of analgesic use for low back pain and its related activity limitation. Engaging in moderate-vigorous and leisure physical activity as well as minimizing sedentary time and physical workload has the potential to reduce the risk of activity limitation and the need for analgesic use in people with low back pain.