The epidemiology of Lp-PLA(2): distribution and correlation with cardiovascular risk factors in a population-based cohort.

Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is an enzyme that is produced by inflammatory cells (macrophages, T-lymphocytes and mast cells) and hydrolyzes oxidized phospholipids in LDL. Several epidemiology studies indicate that Lp-PLA(2) appears to be an independent marker of cardiovascular risk. This study was conducted to define the distribution of Lp-PLA(2) in a large population-based cohort and to determine associations between Lp-PLA(2) and other risk factors for CVD. The study group consisted of participants from the Malmö Diet and Cancer study (1992-1994). Lp-PLA(2) (activity and mass) was measured from samples obtained at baseline for 5402 participants (3167 women). A strong correlation was observed between Lp-PLA(2) activity and mass in this study (r=0.57). Highest correlations were observed between Lp-PLA(2) activity and LDL (r=0.45) and LDL/HDL ratio (r=0.54) and a strong inverse correlation to HDL (r=-0.31). The correlations between Lp-PLA(2) mass and lipids were not as strong as the correlation between activity and lipids. Lp-PLA(2) activity and mass were correlated with increased ultrasound determined carotid intima-media thickness. We conclude that Lp-PLA(2) is strongly correlated with several cardiovascular risk factors, especially lipid fractions, and with the degree of carotid artery atherosclerosis. However, the measured variables accounted for only 19% and 35% of the variation in Lp-PLA(2) mass and activity respectively.