Resumen de Lipoprotein-Associated Phospholipase A^sub 2^ Mass and Activity and Risk of Cardiovascular Disease in a Population With High Prevalences of Obesity and Diabetes: The Strong Heart Study
Jorge Kizer, Jason Umans, Jianhui Zhu, Richard Devereux, Robert Wolfert, Elisa T. Lee, Barbara V. Howard
To investigate the association of lipoprotein-associated phospholipase A^sub 2^ (LpPLA^sub 2^) mass and activity with incident cardiovascular disease (CVD) in a population with high prevalences of insulin resistance and diabetes, conditions for which epidemiological data remain sparse. We conducted a nested, case-control study (n = 1,008) within a population-based cohort of American Indians. Case subjects were defined by incidence of first-ever CVD up to 10 years later. Control subjects comprised participants free of CVD events during the follow-up period who were frequency matched to case subjects by age, sex, and diabetes status. LpPLA^sub 2^ mass and activity were measured using commercially available assays. LpPLA^sub 2^ mass and activity were moderately correlated with each other (r = 0.30), but only LpPLA^sub 2^ activity exhibited moderate correlations with lipid fractions. After extensive adjustment for covariates, both LpPLA^sub 2^ measures were significantly associated with incident CVD, but the relationship was inverse for LpPLA^sub 2^ mass (highest versus lowest tertile, relative risk [RR] 0.55 [95% CI 0.39-0.79]) and positive for LpPLA^sub 2^ activity (highest versus lowest tertile, 1.65 [1.12-2.42]). These associations were similar when participants with and without diabetes were examined separately. In this population-based cohort enriched with dysmetabolic phenotypes, LpPLA^sub 2^ mass and activity showed divergent associations with CVD. The inverse relationship for LpPLA^sub 2^ mass is contrary to observations from predominantly nondiabetic populations and will require independent replication. Whether this finding relates to redistribution of LpPLA^sub 2^ to lipoprotein classes where it is less atherogenic or reflects incomplete measurement of LpPLA^sub 2^ mass associated with altered lipoprotein composition in insulin resistance warrants further investigation.
