Abstract 4036: Lipoprotein-Associated Phospholipase A2 (Lp-PLA2) Independently Predicts Incident Coronary Heart Disease (CHD) in an Apparently Healthy Older Population: The Rancho Bernardo Study
Background: Serum levels of lipoprotein-associated phospholipase A2 (Lp-PLA2), an enzyme that hydrolyzes oxidized phospholipids to yield potentially pro-atherogenic particles, have been associated with coronary heart disease (CHD). We sought to determine whether Lp-PLA2 levels predict incident CHD in community-dwelling older adults without known CHD, independent of classic heart disease risk factors and the inflammatory markers, C-reactive protein (CRP) and IL-6.
Methods: Participants were 577 men and 500 women, ages 40 to 89 (median=72), who had no known CHD at baseline (1984–87) when blood samples and risk factor data were collected. Serum Lp-PLA2 levels were measured on archived samples in 2005 (PLAC, diaDexus, Inc). Participants were followed annually through 2002 for CHD events (fatal or non-fatal myocardial infarction, angina, or coronary revascularization). Cox proportional hazards regression models were used to examine the association of Lp-PLA2 with incident CHD.
Results: Lp-PLA2 levels did not differ by sex, and were positively correlated with age (r = 0.07), body mass index (r = 0.11), LDL (r = 0.37), triglycerides (r = 0.25), CRP (r = 0.09), and IL−6 (r = 0.08), and negatively correlated with HDL (r = −0.27). CHD events were reported in 228 participants during a mean follow-up of 16 years; 38% were fatal. Participants with Lp-PLA2 levels in the 2nd, 3rd, and 4th quartiles had a significantly increased risk of CHD compared with those in the 1st quartile, after adjusting for age and sex (Table⇓). This association persisted after adjusting for other CHD risk factors, and was only marginally attenuated after adjusting for CRP.
Conclusions: Elevated Lp-PLA2 levels independently predict CHD events in apparently healthy older adults, independent of CHD risk factors.