Associations of noninvasive measures of adiposity with aortic stiffness and microvascular function: The Jackson Heart...

Studies suggest that vascular function measures may be more strongly associated with body fat distribution than global adiposity indices.

In Jackson Heart Study participants at examination 2 (2007-2009), we assessed anthropometric obesity indices (body mass index and waist-to-height ratio) and visceral and subcutaneous adipose tissue volume via multidetector computed tomography (CT) scanning. Subsequently, a subset of participants underwent ancillary evaluation of arterial hemodynamics (2012-2017) to assess measures of aortic stiffness (carotid-femoral pulse wave velocity [CFPWV], forward wave amplitude, and characteristic impedance) and microvascular function (brachial arterial flow velocity before and after reactive hyperemia). We used multivariable linear regression models, adjusted for cardiovascular disease risk factors, to relate adiposity measures with arterial hemodynamic measures.

In 1276 participants (mean age 63 years, 66% women), higher body mass index was associated with lower negative inverse CFPWV (niCFPWV, estimated β per SD=-0.8±0.02; P=0.001) and characteristic impedance (β=-0.08±0.03; P=0.004). However, higher visceral adipose volume was associated with higher niCFPWV (β=0.14±0.03; P<0.001) and forward wave amplitude (β=0.08±0.03; P=0.002) in multivariable models that further adjusted for body mass index. Additionally, higher waist-to-height ratio (β=0.09±0.03; P=0.001) and body mass index (β=0.10±0.03; P<0.001), but not visceral or subcutaneous adiposity, were related to higher baseline brachial flow velocity. Adiposity measures were not related to hyperemic brachial flow velocity.

Regional and global adiposity measures may have differing associations with aortic stiffness and microvascular function. Visceral fat may represent a more specific and pathophysiologically-relevant fat depot with direct links to vascular dysfunction. Assessing fat distribution, not just overall adiposity, may be more important when evaluating cardiovascular risk.