Abstract 1093: A Prospective Comparison of NMR-Measured Large Versus Small LDL particles with Incident CHD in 27,673 Initially Healthy Women
Background LDL comprises both large and small particles. However, there is controversy as to which is associated with higher coronary risk and whether smaller LDL size carries higher risk.
Methods and Results In a prospective cohort of 27,673 initially healthy women, baseline levels of small and large LDL particle number (LDL-P) were measured by proton nuclear magnetic resonance spectroscopy (NMR); average LDL size (LDL-sz) was also determined by NMR. Small and large LDL-P were inversely correlated (r -0.52). Small LDL-P correlated inversely with LDL-sz (-0.94); conversely, large LDL-P correlated positively with LDL-sz (0.75). During a follow-up of 11 years, 668 incident coronary heart disease (CHD) events occurred. Using the lowest quintile as the reference, and adjusting for age, smoking, blood pressure, diabetes, menopause, hormone use, and body mass index, but without adjusting for small/large LDL particle correlation, small LDL-P was associated with incident CHD, but large LDL-P was not (Table⇓). When both small and large LDL-P were included in the same model, both were significantly associated with CHD, with higher quintiles of small LDL-P having greater risk estimates compared with large LDL-P quintiles (Table⇓). On a per-particle basis, and after adjusting for small/large LDL particle correlation and risk factors, each 100 nmol/L increment in small and large LDL-P was associated with 7.4% and 7.1% higher CHD risk, respectively; P<0.001 for both. LDL-sz was not significant after accounting for LDL-P and risk factors (P=0.68).
Conclusions Both small and large LDL particles, measured by NMR, were associated with incident CHD after accounting for small/large correlations and risk factors, with small LDL particles having a magnitude of risk greater than large LDL on a per-quintile basis but similar risk on a per-particle basis. NMR-measured smaller LDL size was not associated with increased risk after accounting for LDL-P and risk factors.