Association of obesity with arterial stiffness: The Multi-Ethnic Study of Atherosclerosis (MESA)

Arterial stiffness (AS) and obesity are recognized as important risk factors of cardiovascular disease (CVD). The purpose of this study was to investigate the relationship between AS and obesity. AS was defined as high augmentation index (AIx) and low C1 and C2 in participants enrolled in the Multi-Ethnic Study of Atherosclerosis at baseline. We compared AIx, C1, and C2 by 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). The obesity-AS association was tested across 10-year age intervals. Among 6177 participants (62 +/- 10 years old, 52% female), a significant inverse relationship was observed between obesity and AS. After adjustments for CVD risk factors, participants with a BMI > 40 kg/m(2) had 5.4% lower AIx (mean difference [Delta] = -0.82%; 95% CI: -1.10, -0.53), 15.4% higher C1 (Delta = 1.66 mL/mmHg x10; 95% CI: 1.00, 2.33), and 40.2% higher C2 (Delta = 1.49 mL/mmHg x100; 95% CI: 1.15, 1.83) compared to those with a BMI < 25 kg/m(2) (all p for trend < 0.001). Participants with a WHR > 1 had 5.6% higher C1 ( increment = 0.92 mL/mmHg x10; 95% CI: 0.47, 1.37) compared to those with a WHR < 0.85. The WHR had a significant interaction with age on AIx and C2, but not with BMI; the inverse relationships of the WHR with AIx and C2 were observed only in participants < 55 years between the normal (WHR < 0.85) and the overweight (0.85 <= WHR < 0.99) groups. Different associations of WHR and BMI with arterial stiffness among older adults should be further investigated.