Abstract P242: Association of Obesity With Arterial Stiffness: The Multi-Ethnic Study of Atherosclerosis (MESA)

Abstract

Background: Arterial stiffness is recognized as an important subclinical marker of cardiovascular disease (CVD). However, the relationship between obesity and arterial stiffness is unclear. Methods: Applanation tonometry was used to estimate arterial stiffness, defined as high augmentation index (AIx) and low C1 and C2 in participants enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA) at baseline. Analysis of covariance was used to compare AIx, C1, and C2 across categories of body mass index (BMI) (<25, 25-29.9, 30-39.9, > 40 kg/m 2 ) and waist-hip ratio (WHR) (<0.85, 0.85-0.99, ≥1). Age-obesity interaction was tested among obesity groups across age categories (45 - 54, 55 - 64, 65 - 74, and 75 - 84 years old). Results: Among 6,177 participants (mean age 62±10 years, 52% female), there was significant inverse relationship between obesity and arterial stiffness. After adjustments for CVD risk factors, participants with BMI > 40 kg/m 2 had 5.4% lower AIx (mean difference [Δ] = -0.83; 95% CI, -1.12 - -0.54), 13.5% higher C1 (Δ = 1.40; 95% CI, 0.73 - 2.07), and 41.2% higher C2 (Δ = 1.53; 95% CI, 1.19 - 1.88) compared to participants with BMI < 25 kg/m 2 (all p for trend <0.001). Participants with WHR ≥ 1 had 1.7% lower AIx (Δ = -0.26; 95% CI, -0.46 - -0.06), 6.1% higher C1 (Δ = 0.98; 95% CI, 0.53 - 1.43), and 6.1% higher C2 (Δ = 0.28; 95% CI, 0.05 - 0.51) compared to those with WHR <0.85 (all p for trend < 0.05). WHR had a significant interaction with age on AIx and C2, and the inverse relationship between WHR and arterial stiffness was only observed in participants aged < 55 years. Conclusions: Obesity as measured by BMI and WHR was associated with lower arterial stiffness presented as lower AIx and higher C1 and C2. There was a significant age interaction with WHR on AIx and C2, but not with BMI. Differential effects of WHR versus BMI on arterial stiffness in older adults should be further investigated in future studies.