Abstract 17130: Lipids, Lipoprotein Subclasses, and Ankle Brachial Index in the Multi-Ethnic Study of Atherosclerosis
Introduction: Dyslipidemia is an established risk factor for atherosclerosis, but traditional measures of LDL concentration are inconsistent in prediction of peripheral arterial disease. Measurement of total LDL particle number and LDL subfractions may improve PAD risk assessment.
Methods: MESA is a prospective observational study from 4 ethnic groups free of cardiovascular disease at baseline. LDL concentration (LDLc ), particle number (LDLp) and size were measured using nuclear magnetic resonance spectroscopy (NMR). PAD was defined as ABI <=0.9. Logistic regression was used to examine the association between lipid quartiles and PAD, and odds ratios (OR) were reported for the top quartile of each measure relative to the lowest quartile. Models were adjusted for age, gender, ethnicity, hypertension, diabetes, BMI, smoking, physical activity, education, GFR, and use of lipid lowering drugs.
Results: PAD prevalence: 6655 subjects had ABI & lipid measurements at baseline. 250 had ABI<=0.9. PAD cases had higher LDLc (115 vs 111 mg/dL, p=0.03) & LDLp (1356 vs 1310 nmol/L p=0.05). After adjustment there was a significant association of LDLp with PAD prevalence (OR 1.9, 95% CI 1.1-3.5) that persisted after adjustment for baseline LDLc. No association was present for LDLc (1.2, 0.7-2.1). PAD progression: 5558 subjects with normal ABI at baseline had lipids & ABI at 5.5 years. 170 progressed to ABI <=0.9 or >1.4. Neither LDLc nor total LDLp were associated with progression (OR 0.6, 0.3-1.1 and 1.9, 0.9-3.8). Particle subfractions: The number of small LDL particles was significantly associated with both prevalence of (OR 2.2, 1.5-3.3) & progression to PAD (OR 1.7, 1.1-2.7) in fully adjusted models. We observed no significant interactions with ethnicity or gender.
Conclusion: Measurements of lipid particle numbers, particularly the number of small LDL particles, are associated with PAD in the MESA population independent of LDLc, while LDLc was no longer a predictor of incident ABI when controlling for LDLp. This suggests that particle number contributes important predictive information beyond conventional lipid measures.
- © 2010 by American Heart Association, Inc.