High plasma lecithin:cholesterol acyltransferase activity does not predict low incidence of cardiovascular events: Possible attenuation of cardioprotection associated with high HDL cholesterol

The cholesterol esterifying enzyme, lecithin:cholesterol acyltransferase (LCAT), is crucial in high density lipoprotein (HDL) metabolism. The role of LCAT activity on incident cardiovascular disease (CVD) is unknown. We determined the association of incident CVD with plasma LCAT activity, and evaluated whether LCAT may modify the cardioprotective effect of higher HDL cholesterol. In a community-based prospective nested case-control study (PREVEND cohort), an exogenous substrate assay was used to measure plasma LCAT activity in 116 men who developed CVD (cases) and in 111 male controls. Plasma LCAT activity was 5% higher in cases (P = 0.027) in association with higher total cholesterol, non-HDL cholesterol and triglycerides. Age-adjusted incident CVD was increased with higher LCAT activity (continuous variable: hazard ratio (HR) 1.23; 95% CI 1.01-1.49, P = 0.037; upper quartile vs. lowest 3 quartiles: HR 1.60; 95% CI 1.07-2.39, P = 0.021). This relationship was not significant after adjustment for lipids. Compared to subjects with HDL cholesterol above the median and lower LCAT activity (lowest 3 quartiles) the age-adjusted cardiovascular risk was elevated in subjects with similarly higher HDL cholesterol and higher LCAT activity (HR 2.38; 95% CI 1.27-4.49, P = 0.007), lower HDL cholesterol and lower LCAT activity (HR 2.58; 95% CI 1.64-4.49, P < 0.001) and lower HDL cholesterol and higher LCAT activity (HR 2.76; 95% CI 1.58-4.83, P < 0.001). These HRs were unchanged after non-HDL cholesterol and triglyceride adjustment. In conclusion, high plasma LCAT activity does not predict reduced CVD risk, and may attenuate cardioprotection associated with higher HDL cholesterol.