Discordance between apolipoprotein B, calculated low density lipoprotein-cholesterol and non-high density lipoprotein cholesterol measurements in plasma

Abstract

Introduction: Routine estimation of the majority of the atherogenic risk attributable to lipoproteins is done by the measurement of cholesterol content of the low density lipoprotein (LDL) as LDL-cholesterol (LDL-C). Non-high density lipoprotein cholesterol (n-HDL-C) and Apolipoprotein B (Apo B) measurements have also been used as indices of risk as they account for other atherogenic molecules beyond LDL. We evaluate for discordance between these indices. Methodology: Fasting plasma total cholesterol, triglycerides, high density lipoprotein cholesterol, Apo B and glucose were measured on healthy non-diabetic participants. Low density lipoprotein- Cholesterol, non-HDL-C and BMI were calculated. Low density lipoprotein- Cholesterol LDL-C, apolipoprotein B and non-HDL cholesterol were grouped into percentiles. Individuals were discordant if either their LDL-C or non-HDL values belonged to a percentile category different from their percentile category for Apo B. Results: A discordant result (apolipoprotein B /LDL-C or apolipoprotein B /non-HDL-C) was seen in 55 (22%) of the 252 participants. Discordance was more frequent between apolipoprotein B and non-HDL cholesterol, occurring in 50 (20%) persons than between apolipoprotein B and LDL-C, 21 (8.4%). Discordance -was associated a body mass index (BMI)≥25kg/m2 (p = 0.039) and ≥ 30kg/m2 (p = 0.008) and the median BMI of persons who were discordant was also higher than those who were not 26.2 kg/m2 vs. 25.0 kg/m2, p = 0.018, respectively. Conclusion: Discordance between Apo B and the calculated LDL-C and non-HDL is common among overweight and obese persons. It may provide a useful insight into the presence of atherogenic small dense LDL particles among these persons.