(P24-041-23) Effects of LDL Phenotype and Differences in Risk Stratification in Response to Dairy Fat Consumption

Objectives: Standard lipid measurements (TC, LDL-C) have been traditionally used to assess risk for CVD. Recent research suggests that cholesterol subfractions such as LDL particles (LDL-P) may be better predictors. However, LDL-P distributions are highly variable. This interindividual variability can be harnessed to classify individuals into different phenotypes which differ in their CVD risk. It is unknown how these phenotypes influence the response to consumption of fat, particularly dairy fat. The aim of this analysis was to investigate the effect of the LDL phenotype and differences in risk stratification in response to dairy fat consumption in a mixed cohort.

Methods: This analysis used bio-banked samples from a 6-wk intervention of 42g dairy fat/day (cheese, butter, or cheese + butter) in n=127 participants (≥50y, BMI ≥25kg/m²). LDL-P concentration (nmol/L) and size (nm) was measured using NMR spectroscopy. Firstly, participants were categorised based on LDL particle size (nm) into LDL phenotype A (21.3-23.0 nm) or B (18.0-21.2 nm). Second, LDL-P conc. was used for risk stratification based on MESA guidelines (normal v increased risk) and finally, ATP III guidelines were used to assess risk based on LDL-C conc.

Results: LDL particle size (nm) showed 15% of participants as phenotype A and 85% as higher risk phenotype B at baseline. After intervention, there was a change in LDL phenotype in a small percentage, where 15% changed from B to A and 8% changed from A to B, 77% exhibited no change. When risk was categorised using LDL-P conc. (MESA), 11% changed from increased risk to normal risk, and 6% from normal to increased risk, with 83% exhibiting no change. Results were similar when risk was categorised using LDL-C (ATP III), whereby after intervention 17% changed from increased risk to normal risk, 4% from normal to increased risk, and 79% didn’t change.

Conclusions: Significant variation exists in categorisation of ‘at risk’ using different guidelines. Following a 6-wk dairy fat intervention, some individuals exhibited a shift towards a more favourable LDL pattern, or to a lower CVD risk category, but the majority did not change. Inter individual differences must be considered when looking at CVD risk stratification, and more research is needed to define the most appropriate way to identify and determine change in risk.

Funding Sources: Food for Health Ireland, Enterprise Ireland