Lipid and brain volumetric measures in multiple sclerosis patients: findings from a large observational study

Objectives This study aimed to investigate relationships between cholesterol profile, brain volumetric MRI, and clinical measures in a large observational cohort of multiple sclerosis (MS) patients. Materials and methods We included 1.505 patients with 4.966 time points including complete lipid, clinical, and imaging data. The time among lipid, brain MRI and clinical measures was under 90 days. Cross-sectional statistical analysis at baseline was performed using an adjusted linear regression and analysis of longitudinal lipid and MRI measures data was performed using adjusted linear mixed models. Results We found associations between higher high-density lipoprotein cholesterol (HDL-C) and lower brain parenchymal fraction (BPF) at cross-sectional analysis at baseline (B = -0.43, CI 95%: -0.73, -0.12, p=0.005), as well as in longitudinal analysis over follow-up (B = -0.320.072, chi(2)=36.6; p=<0.001). Higher HDL-C was also associated with higher T2-lesion volume in longitudinal analysis (B=0.11 +/- 0.023; chi(2)=23.04; p=<0.001). We observed a weak negative association between low-density lipoprotein cholesterol (LDL-C) levels and BPF at baseline (B = -0.26, CI 95%: -0.4, -0.11, p=<0.001) as well as in longitudinal analysis (B = -0.06 +/- 0.03, chi(2)=4.46; p=0.03). T2-LV did not show an association with LDL-C. We did not find any association between lipid measures and disability. The effect of lipid levels on MRI measures and disability was minimal (Cohen f2<0.02). Conclusions Our results contradict the previously described exclusively positive effect of HDL-C on brain atrophy in patients with MS. Higher LDL-C was weakly associated with higher brain atrophy but not with higher lesion burden.