9-HODE associates with thalamic atrophy and predicts white matter damage in multiple sclerosis

•It is unclear how bioactive lipid mediators relate to brain tissue damage on MRI.•Lower baseline 9-HODE levels correlated with worse thalamic atrophy in RRMS.•Lower baseline levels of 9-HODE predicted worsening of white matter damage.•Bioactive lipid mediators may reveal lipid-driven MS pathophysiological mechanisms.