Nuclear magnetic resonance (NMR) spectroscopy is being used to determine th
e concentrations of very low-density lipoprotein (VLDL), low-density lipopr
otein (LDL), and high-density lipoprotein (HDL) subclasses of different siz
e. These subclasses have unequal associations with coronary heart disease.
Nuclear magnetic resonance distinguishes among the subclasses on the basis
of slight differences in the spectral properties of the lipids carried with
in the particles, which vary according to the diameter of the phospholipid
shell. Studies using NMR spectroscopy have shown that individuals with elev
ated triglycerides are likely to have higher-risk lipoprotein subclass prof
iles. Triglyceride-rich lipoproteins drive the metabolic reactions that pro
duce LDL of abnormal size and cholesterol content. The quantities of these
abnormal LDL particles and the associated risk of coronary heart disease ar
e underestimated by conventional cholesterol measurements. Nuclear magnetic
resonance spectroscopy measures lipoprotein subclasses directly and effici
ently, and produces information that may improve the assessment and managem
ent of cardiovascular disease risk.