Lipoprotein Particle Size Predicts Development of Diabetes

The lipoprotein particle size and concentration can be measured by nuclear magnetic resonance (NMR) spectroscopy. This technique simultaneously quantifies the size and concentration of lipoprotein particles expressed each as an average particle size in nanometers or as lipoprotein particle concentration (in particle mol/L).

A prospective study, carried out at the Harvard Medical School, (Boston, MA, USA), followed 26,836 initially healthy women for 13 years for incident type-2 diabetes. During that time, 1,687 developed the disease. The study found that larger low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles were associated with lower risk, and smaller LDL and HDL particles were associated with higher risk of diabetes. Even in women with normal triglyceride and HDL cholesterol measured by standard tests, having smaller LDL particles imparted higher risk of diabetes.

Doctors typically look for increases in glucose and triglycerides, and decreases in HDL cholesterol, to determine if a patient is becoming prediabetic. Even before changes in glucose levels are detectable, there are significant changes in the metabolism of cholesterol and triglycerides. These standard lipid tests quantify the cholesterol or triglyceride content of lipoproteins, without providing size-specific lipoprotein particle information. NMR lipoproteins examined in individuals with insulin resistance or type-2 diabetes with small LDLs, small HDLs, and large very low-density lipoproteins (VLDLs) associated positively and large HDLs associated inversely with insulin resistance measured by the euglycemic clamp technique or the frequently sampled intravenous glucose tolerance test .

Samia Mora, M.D., of Harvard Medical School, said, "Our findings indicate for the first time that even before the onset of clinical type 2 diabetes, the size and number of the lipoprotein particles may indicate which women go on to develop future disease. This could provide an important opportunity for a woman with a normal blood glucose, but an abnormal NMR lipoprotein test result, to intervene early by following a healthy diet, losing weight, and increasing her physical activity level, all known ways to reduce her chance of developing diabetes even years before she gets a high glucose reading.” The results of the study were published in May 2010 issue of Diabetes.

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