Regional body composition as a determinant of arterial stiffness in the elderly

OBJECTIVE: To estimate the relation of precisely measured regional body composition with peripheral and central arterial stiffness in the elderly. METHODS: We investigated 648 participants (mean age 69.0 +/- 6.0 years) of the Hoorn Study, a population-based cohort study. Trunk fat, leg fat, trunk lean and leg lean mass were distinguished by dual-energy X-ray absorptiometry. We used ultrasound to measure the distensibility and compliance of the carotid, femoral and brachial arteries, and carotid Young's elastic modulus, as estimates of peripheral stiffness. As estimates of central stiffness we measured carotid-femoral transit time, aortic augmentation index and systemic arterial compliance. RESULTS: After adjustment for sex, age, height, mean arterial pressure, leg lean and leg fat mass, a larger trunk fat mass was consistently associated with higher peripheral arterial stiffness (standardized beta (beta) of mean Z-scores of all three large arteries -0.24, P < 0.001). In contrast, larger leg fat mass (beta = 0.15, P = 0.009) and leg lean mass (beta = 0.09, P = 0.20) were associated with lower peripheral arterial stiffness. Trunk or leg fat mass were not associated with central arterial stiffness. Leg lean mass, however, was consistently associated with lower central arterial stiffness (beta = 0.29, P < 0.001). CONCLUSIONS: Trunk fat mass may have adverse effects on peripheral, but not on central arterial stiffness, while leg fat was not harmful and may have a slight protective effect. Larger leg lean mass was the most important determinant of lower central arterial stiffness. These results provide a pathophysiological framework to explain not only the higher cardiovascular risk in individuals with larger trunk fat mass, but also the reduced cardiovascular risk in individuals with larger leg lean and fat mass.