Baraliakos X, Richter A, Feldmann D, et al. - This study was sought to distinguish factors correlated with the presence and extension of spinal and sacroiliac joints (SIJ)–MRI lesions suggestive of axial spondyloarthritis (axSpA) in a population-based cohort (Study of Health in Pomerania) aged < 45 years. Via two trained blinded readers, spinal (sagittal T1/T2) and SIJ (semicoronal STIR sequences) MRIs were assessed. They analyzed MRIs of 793 volunteers. In the general population aged < 45 years, these population-based data support the hypothesis of mechanic strain contributing to bone marrow oedema (BME) and the role of HLA-B27+ as a severity rather than a susceptibility factor for SIJ–BME.