Associations Between Back Pain Incidence, and Physical Activity and Sedentary Behaviors: A Prospective Cohort Study With Data From Over 365 000 Participants.

* OBJECTIVE: To examine the associations between (1) various types of physical activity and the risk of back pain incidence, and (2) the influence of substituting sedentary behaviors with physical activities on back pain incidence. * DESIGN: A prospective cohort study. * METHODS: We analyzed UK Biobank data collected from 365 307 participants who were free of back pain at baseline. The exposures were total, light, moderate, and vigorous physical activity, and sedentary behaviors. The outcome was back pain incidence. The main statistical models were the Cox proportional hazard model and the isotemporal substitution model. * RESULTS: In the follow-up time (median, 12.97 years; interquartile range, 12.10-13.71), 25 189 individuals developed back pain. The associations between all types of physical activity and incident back pain were significantly nonlinear (P<.001) among the general population and other subgroups. High physical activity was associated with a decreased risk of back pain compared with no physical activity. The lowest risk occurred in the 1801-to-2400 MET-min/week (metabolic-equivalent minutes per week) subgroup of total physical activity (hazard ratio [HR] = 0.64; 95% CI: 0.59, 0.69), approximately consisting of 1200, 600, and 600 MET-min/week of light, moderate, and vigorous physical activity, respectively. Extremely high vigorous physical activity was related to high risk, specifically in males (HR = 1.13; 95% CI: 1.02, 1.25). Replacing 1 hour/day of sedentary behaviors with an equal time of physical activity reduced the risk of incident back pain by 2% to 8% (P<.05). * CONCLUSION: Physical activity was related to a reduced risk of back pain incidence (except over high vigorous physical activity). Substituting sedentary behaviors with physical activities reduced the risk of future back pain. [ABSTRACT FROM AUTHOR]