Study design: A prospective 9-year follow-up study involving randomized matched subgroups of 15-year-old schoolchildren with or without low back pain at baseline.
Objectives: To evaluate the long-term persistence of initially reported recurrent low back pain, and to examine the significance of abnormalities found in magnetic resonance imaging of lumbar discs in individuals 15 and 18 years of age as possible contributors to persistently recurrent low back pain.
Summary of background data: In surveys among children and teenagers during the past few years, as many as half of all children in a community report a history of low back pain. The current results, in accordance with previous findings, indicate that there is a subgroup of adolescents with more chronic symptoms which, in the authors' opinion, deserves more attention. Disc disease accompanying low back pain is a key issue both in research and clinical practice. The significance of early degenerative findings in the lumbar discs is not known.
Methods: In the survey of 14-year-olds (n = 1503), a subgroup (7.8%) with recurrent low back pain was found. A random sample of individuals with recurrent low back pain (n = 40) and an equal number of completely asymptomatic control subjects were selected for a comparative study. The selected groups were examined by magnetic resonance imaging at 15 and 18 years of age. The participation rate of youth at 14, 18, and 23 years of age for all three questionnaires was 82% (29 boys and 33 girls). Imaging data were interpreted by two blinded radiologists experienced in low-field-strength magnetic resonance imaging. In calculations of relative risks, the participants reporting recurrent low back pain in all phases of the study were compared with participants who had no persistently recurrent pain.
Results: Eleven participants (35%) in the original group with low back pain persistently reported recurrent pain. In 15-year-old participants with disc degeneration, the relative risk of reporting recurrent low back pain up to the age of 23 years was 16 (95% confidence interval 2.2-118) compared with those having no disc degeneration. In addition, disc protrusion and Scheuermann-type changes at 15 years contributed to the risk of persistently recurrent low back pain.
Conclusions: The authors' earlier findings already favored the hypothesis of a causal relation between the early evolution of a degenerative process of lower lumbar discs and recurrent low back pain in the near future. The current results further strengthen this hypothesis, indicating that individuals with disc degeneration soon after the phase of rapid physical growth not only have an increased risk of recurrent low back pain at this age, but also a long-term risk of recurrent pain up to early adulthood.