Subtype‑specific associations between serum lipid profiles and disease severity in patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a heterogeneous neurodegenerative disorder. Notably, the differences in lipid metabolism between bulbar- and limb-onset subtypes of ALS remain unclear, particularly in non-Western populations. The present study investigated serum lipid profiles in a Chinese cohort of patients with ALS to explore their associations with disease severity and clinical subtypes. A retrospective, cross-sectional study was conducted, involving 158 patients with ALS and 62 matched healthy controls. Serum lipid parameters, including total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), small dense LDL cholesterol (sdLDL-c), apolipoprotein A-1 (ApoA1), apolipoprotein B (ApoB) and the TG/HDL ratio, were compared between the groups. Correlation analyses and multivariable linear regression models incorporating phenotype x lipid interaction terms were conducted after adjusting for age, sex, body mass index and disease duration. Patients with ALS exhibited significantly higher TC, TG, LDL, sdLDL-c, ApoA1, ApoB and TG/HDL ratios than controls. Subtype-specific analyses revealed different associations; in bulbar-onset ALS, higher sdLDL-c and TG/HDL ratios were associated with better functional status, whereas higher HDL and ApoA1 levels were negatively correlated with functional status. By contrast, in limb-onset ALS, higher sdLDL-c and ApoB levels were associated with worse function. Interaction analyses confirmed significant phenotype modification for sdLDL-c, TG/HDL ratio, HDL and ApoA1. These results suggest that lipid-severity relationships in ALS vary by subtype, indicating metabolic heterogeneity across phenotypes and supporting the potential of specific lipid parameters as exploratory markers for disease monitoring.