The most physically active Danish adolescents are at increased risk for developing spinal pain: a two-year prospective cohort study

BACKGROUND The overall aim of this study was to determine to what extent objectively measured physical activity in a school-based sample aged 11-13 years predicted incident cases of spinal pain (neck pain, mid back pain or low back pain) over the following 2 years. METHODS Data were collected at baseline (2010) and 2 years later in a school-based prospective cohort study. Spinal pain was assessed via an e-survey that the participants completed during school time. Participants who, at baseline, reported never having had spinal pain were included in the study. An incident case of spinal pain was defined as a report of pain in at least one spinal area at follow-up. Physical activity was measured objectively using the Actigraph GT3X Triaxial Activity Monitor for 1 week. RESULTS Objectively measured sedentary activity, moderate-to-vigorous physical activity and vigorous physical activity were generally not predictive of the 2-year incidence of spinal pain. However, 10% of participants with the highest proportion of the day spent in vigorous physical activity were at increased risk of reporting spinal pain at follow-up with a relative risk (RR) of 1.44 (95% CI 1.09 to 1.91). For the overall physical activity, the RR was 1.03 (95% CI 1.01 to 1.05) for reporting spinal pain at follow-up. CONCLUSIONS In general, physical activity did not affect the risk of spinal pain during follow-up, but the 10% most active adolescents were at increased risk of developing spinal pain. Thus, vigorous physical activity appears to be a risk factor for spinal pain in adolescents.