Spine
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A prospective cross-sectional study. ⋯ 2.
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Epidemiological study based on cross-sectional data of a representative sample. ⋯ 3.
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Retrospective cohort. ⋯ 3.
A prospective cross-sectional study. ⋯ 2.
Epidemiological study based on cross-sectional data of a representative sample. ⋯ 3.
Retrospective cohort. ⋯ 3.