Associations of metabolic health and obesity with apolipoprotein B and low-density lipoprotein cholesterol discordance in a large Korean cohort

BACKGROUND Discordance between apolipoprotein B (apoB) and low-density lipoprotein cholesterol (LDL-C) levels is frequently observed in individuals with metabolic disorders and may contribute to underestimated cardiovascular risk. Population-based data on LDL-C discordance in East Asians, particularly in metabolically healthy individuals, remain limited. OBJECTIVE We aimed to investigate the distribution of apoB relative to LDL-C and non-high-density lipoprotein cholesterol (non-HDL-C) levels and assess the prevalence and determinants of apoB–LDL-C discordance. METHODS We analyzed data from 411,125 Korean adults who underwent health checkups between 2011 and 2023. Participants with a history of cardiovascular disease or lipid-lowering therapy were excluded from the study. ApoB–LDL-C (and apoB–non-HDL-C) discordance was quantified using residuals from a linear regression model. Individuals were classified as discordant-high (residuals > 75th percentile), discordant-low (residuals < 25th percentile), or concordant (residuals between the 25th and 75th percentiles). Subgroup analyses were performed for metabolic status, obesity phenotype, and lifestyle or family risk factors. RESULTS Substantial variability in apoB levels was observed at each LDL-C and non-HDL-C level. ApoB–LDL-C discordance patterns between apoB and non-HDL-C were similar to those observed with apoB and LDL-C, though with smaller residual differences. Discordance was most pronounced in metabolically unhealthy obese individuals, followed by metabolically unhealthy lean individuals, and metabolically healthy individuals ( P < .001), indicating that metabolic health is a stronger determinant of discordance than obesity. CONCLUSIONS ApoB–LDL-C discordance is common, even among metabolically healthy individuals, and is primarily driven by metabolic dysfunction rather than by obesity. ApoB measurements should be included in routine cardiovascular risk assessments.