Association of A Body Shape Index, But Not Body Mass Index, with Seated Arterial Stiffness Evaluated by Innovative Cardio-Ankle Vascular Index

BACKGROUND: A Body Shape Index (ABSI) reflects abdominal adiposity independent of body size. Although the cardio-ankle vascular index (CAVI) is linked to ABSI, whether this association extends to innovative CAVI (iCAVI) remains unclear. We developed iCAVI, an arterial stiffness index measured from the aortic valve to the right brachial artery in the seated position and examined its association with ABSI. METHODS: This cross-sectional study included 117 individuals undergoing cardiovascular risk assessment. iCAVI, ABSI, body mass index (BMI), and waist circumference (WC) were evaluated. Associations were assessed using Spearman's correlation and multivariable analyses adjusting for age and sex-adjusted analyses, with further adjustment for hypertension, diabetes mellitus, dyslipidemia, and coronary artery disease. Adjusted iCAVI values across anthropometric tertiles were compared. RESULTS: iCAVI was positively correlated with ABSI (ρ = 0.233, 95% CI [0.048, 0.402], p = 0.012), but not with WC (ρ = -0.054, 95% CI [-0.238, 0.134], p = 0.563) or BMI (ρ = -0.162, 95% CI [-0.339, 0.026], p = 0.081). Age- and sex-adjusted iCAVI increased across ABSI tertiles (2.79, 2.96, and 3.14; p for trend = 0.045). The linear contrast estimate was 0.25 (95% CI [0.01, 0.49]) and remained similar after further adjustment for hypertension, diabetes, dyslipidemia, and coronary artery disease (0.23, 95% CI [-0.02, 0.48]; p for trend = 0.067). CONCLUSIONS: ABSI was positively associated with iCAVI, whereas BMI and WC were not, suggesting that ABSI may capture aspects of body shape associated with arterial stiffness that are not reflected by conventional anthropometric indices.