Oxidized Lipoprotein Biomarker Levels Affected by Age, Ethnicity

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The doubling of IgG MDA-LDL levels was associated with positive CAC and time to MACE.
The doubling of IgG MDA-LDL levels was associated with positive CAC and time to MACE.

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.

Reference

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.

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