Levels of oxidized lipoprotein autoantibodies differ between races and ages, which can affect the risk of subclinical atherosclerosis, according to research presented at the 66th Annual Scientific Session & Expo of the American College of Cardiology in Washington, DC.
Researchers from the University of California, San Diego in La Jolla measured IgG and IgM autoantibodies to malondialdehyde (MDA)-low-density lipoprotein (LDL) and apolipoprotein B-100 immune complexes (ApoB-IC) in 3509 individuals from the Dallas Heart Study. There were 1814 blacks, 1031 whites, and 589 Hispanics who were followed over a median of 10.5 years.
The researchers quantified coronary artery calcium (CAC) scores, abdominal aortic plaque by MRI, and major adverse cardiovascular events (MACE; defined as cardiac death, myocardial infarction, stroke/transient ischemic attack, coronary and peripheral revascularization).
IgG MDA-LDL and IgG and IgM apoB-IC levels were significantly different in the 3 groups. Blacks had the highest levels of IgG MDA-LDL and ApoB-IC, but the lowest levels of IgM ApoB-IC (P <.001 for all). In addition, IgGs increased and IgMs decreased with age, especially in black patients, creating a significant age effect.
The doubling of IgG MDA-LDL levels was associated with positive CAC (odds ratio [OR]: 1.16; 95% CI, 1.01-1.33; P =.035) and time to MACE (OR: 1.41; 95% CI, 1.13-1.76l P =.002) in the entire population (OR: 1.86; 95% CI, 1.22-2.84; P =.004) for the first vs fourth quartile in a multivariable-adjusted Cox regression analysis.
The time to MACE prediction was mostly driven by black patients (OR: 2.64; 95% CI, 1.42-4.92; P =.002). The net reclassification index for time to MACE was 20.4% when IgG MDA-LDL was added to traditional risk factors.
The researchers noted that elevated IgG MDA-LDL levels are associated with a higher risk of subclinical atherosclerosis and may serve as accurate predictors of MACE, especially in black patients. “These findings may contribute to the understanding of differences in race-specific MACEs,” they concluded.
Tsimikas S, Prasad A, Clopton P, et al. Relationship of biomarkers of oxidized lipoproteins to ethnicity, subclinical atherosclerosis and cardiovascular events over a 10.5 year follow-up in the Dallas Heart Study. Abstract 1126-325. Presented at: the 66th Annual Scientific Session & Expo of the American College of Cardiology. March 17-19, 2017; Washington, DC.