Abstract 38: Segment-Specific Association of Body Mass Index with Carotid Plaque and Intima-Media Thickness: The Northern Manhattan Study

Abstract

Objective: Obesity is a risk factor for cardiovascular disease and stroke, and carotid intima-media thickness (IMT) and plaque are markers of subclinical atherosclerotic disease. The differential relationship of body mass index (BMI) to IMT and plaque at different carotid segments has not been studied. In the present analysis, we evaluated the segment-specific association of BMI with IMT and plaque presence in a community-based cohort from the Northern Manhattan Study (NOMAS). Methods and Results: A total of 1653 NOMAS subjects (mean age 69±9 years, 40% male, 18% white, 20% black and 62% Hispanic) underwent B-mode ultrasound examination of the common carotid artery (CCA), internal carotid artery (ICA) and bifurcation (BIF). Generalized linear modeling was performed to evaluate the relations of BMI to IMT or plaque presence in CCA, ICA and BIF, adjusted for age, sex, race-ethnicity, smoking, physical activity, alcohol drinking, systolic and diastolic blood pressure, fasting glucose, LDL, HDL, medications for hypertension, diabetes, and high cholesterol. Overall, the mean BMI was 28±5 kg/m2 (29% obese, 45% overweight). The mean IMT was 0.73±0.09 mm in CCA, 0.64±0.08 mm in ICA, and 0.74±0.10 mm in BIF. The prevalence of plaque was 9% in CCA, 20% in ICA and 53% in BIF. The change in IMT (mm) for per unit BMI increase was largest in CCA (Beta=0.002, P<0.0001), intermediate in ICA (Beta=0.001, P=0.002), and smallest in BIF (Beta=0.0006, P=0.22). Similarly, compared with those with normal weight, obese individuals had larger IMT in CCA (Beta=0.03, P<0.0001) and ICA (Beta=0.02, P=0.01) but not in BIF (Beta=0.006, P=0.40). No association was found between BMI and plaque presence in CCA (P=0.74), ICA (P=0.69), or BIF (P=0.94). There was no significant effect modification by race-ethnicity or sex on the association of BMI with IMT or plaque presence at a specific segment. Conclusion: BMI may be a risk factor for IMT in CCA and ICA rather than BIF or presence of plaque at any specific segment. Given that these carotid segments differ in geometry, shear stress, extracellular matrix structure, and cell composition, further studies are needed to explore the differences in mechanisms underlying the development of atherosclerosis lesions in different carotid segments.