Abstract P177: Discordantly Normal ApoB Relative To Elevated LDL-C In Persons With Metabolic Disorders: A Marker Of Atherogenic Heterogeneity

Abstract

Introduction: A significant proportion of persons with metabolic syndrome, prediabetes, or type 2 diabetes do not develop atherosclerotic cardiovascular disease (ASCVD). Discordantly normal apolipoprotein B (ApoB) relative to elevated LDL-cholesterol (LDL-C) may help to explain underlying heterogeneity in ASCVD risk among these individuals. Hypothesis: We hypothesized that discordantly normal ApoB (<90 mg/dL) relative to elevated LDL-C ( > 100 mg/dL) would be associated with a lower atherosclerosis burden among individuals with metabolic disorders. Methods: There were 331 Bogalusa Heart Study participants with metabolic syndrome (n=107), prediabetes (n=291), or type 2 diabetes (n=34) and LDL-C > 100 who were free of carotid plaque at baseline (2001-02) and underwent carotid ultrasound at follow-up (2013-16). Carotid plaque was defined as a focal wall thickening >1.5 mm. Modified Poisson regression with robust error variance estimated the long-term absence of plaque for normal ApoB after adjusting for established risk factors. Results: Participants were on average 36.3 years old at baseline, 202 (61.0%) were women, and 93 (29.9%) were African American. Overall, LDL-C explained 42.3% of the variability in ApoB as the lipoprotein markers were only modestly correlated (r=0.65). Participants with ApoB <90 (51.1%) were more likely to remain free of carotid plaque compared to those with ApoB > 90 (74.6% versus 57.4%, p=0.001, Figure ). In multivariable modeling, persons with ApoB <90 were 21% more likely to have long-term absence of plaque (RR=1.21, 95% CI: 1.03-1.43), independent of traditional ASCVD risk factors, including LDL-C. Conclusions: More than half of persons with metabolic disorders and elevated LDL-C had normal ApoB with a lower burden of carotid atherosclerosis over 13 years follow-up. ApoB better represents the atherogenic lipid burden among persons with metabolic disorders compared to LDL-C and may be especially helpful for persons with the pattern of high triglycerides and low HDL-cholesterol.