Spine
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Retrospective clinical study. ⋯ 4.
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A prospective cohort study that used a Swedish nationwide occupational surveillance program for construction workers (period of registration from 1971 to 1992). In all, 364,467 participants (mean age at baseline 34 yr) were included in the study. ⋯ 3.
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Retrospective cohort. ⋯ 3.
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Retrospective study of a consecutive series of patients undergoing lumbar spine magnetic resonance imaging (MRI) for low back pain at a single institution. ⋯ 3.