ANNALS EXPRESS: Establishing reference intervals for triglyceride containing lipoprotein sub-fraction metabolites measured using Nuclear Magnetic Resonance Spectroscopy in a UK population.

Background Nuclear magnetic resonance (NMR) allows triglycerides (TG) to be subclassified into 14 different classes based on particle size and lipid content. We recently showed that these sub-fractions have differential associations with cardiovascular disease (CVD) events. We report the distributions and define reference interval ranges for 14 TG-containing lipoprotein sub-fraction metabolites. Methods Lipoprotein sub-fractions using the Nightingale NMR platform were measured in 9,073 participants from 4 cohort studies contributing to the UCL-Edinburgh-Bristol (UCLEB) consortium. The distribution of each metabolite was assessed. Reference interval ranges were calculated for a disease-free population, by sex and age group, and in participants with CVD or type 2 diabetes. We also determined the distribution across BMI and smoking status. Results The largest reference interval range was observed in the medium VLDL sub-class (2.5th 97.5th percentile; 0.08 to 0.68 mmol/L). TG sub-fraction concentrations in VLDL, IDL, LDL and HDL sub-classes increased with increasing age and increasing BMI. TG sub-fraction concentrations were significantly higher in ever smokers compared to never smokers, among those with clinical chemistry measured total TG greater than 1.7 mmol/L, and in those with CVD , and type 2 diabetes as compared to disease-free subjects. Conclusion This is the first study to establish reference interval ranges for 14 TG-containing lipoprotein sub-fractions in samples from the general population measured using the NMR platform. The utility of NMR lipid measures may lead to greater insights for the role of TG in CVD, emphasising the importance of appropriate reference interval ranges for future clinical decision making.