Abstract P198: Cumulative Abdominal Obese-Years and Arterial Stiffness in Older Adults: The Atherosclerosis Risk in Communities (ARIC) Study

Abstract

Introduction: Arterial stiffness quantifies subclinical cardiovascular disease (CVD) and is predictive of athero-thrombotic events and mortality. Time-cumulative measures of obesity may more accurately estimate the lifetime burden of CVD due to obesity by accounting for both duration and intensity. Compared to generalized obesity, abdominal obesity is more consistently associated with vascular outcomes and, specifically, arterial stiffness. We examined whether 20-year cumulative abdominal obese-years is associated with greater arterial stiffness in older adults. Methods: We analyzed 5,177 participants from the ARIC cohort. Cumulative abdominal obesity was defined as the product of waist circumference units above the conventional cutpoints for obesity, 88 cm for women and 102 cm for men, and the years of exposure to that waist circumference. This accounts for obesity exposure over 20 years from the five ARIC visits. Arterial stiffness was measured by pulse wave velocity (PWV) at the fifth ARIC visit. Measures of PWV obtained include: carotid-femoral PWV (cfPWV), brachial-ankle PWV (baPWV), and segment-specific measures [heart-femoral (hfPWV) and femoral-ankle (faPWV)]. Multivariable linear regression, adjusted for age, sex, race, systolic blood pressure and smoking, was used to quantify the change in PWV (cm/s) per unit increase in cumulative abdominal obese-years. Subsidiary analyses examined visit five waist circumference. Hypertension and diabetes were explored as effect modifiers. Results: Among the 5,177 participants (mean age: 75, 43% male, 21% African-American), 66% had cumulative abdominal obese-years greater than zero (range: 1-1595), while 34% were not abdominally obese across any ARIC visit and thus had zero cumulative abdominal obese-years. Participants with higher cumulative abdominal obese-years were more often male, African-American and had a history of diabetes and hypertension. Cumulative abdominal obese-years were associated with lower baPWV (beta=-0.19, 95% CI: -0.23, -0.14), lower faPWV (beta=-0.12, 95% CI: -0.15, -0.09) and lower hfPWV (beta=-0.06, 95% CI: -0.10, -0.03). There was no significant association with cfPWV (beta=-0.03, 95% CI: -0.08, 0.01). The cross-sectional association between visit five abdominal circumference and PWV were similar in magnitude to cumulative abdominal obese-years. Hypertension and diabetes did not modify these associations. Conclusions: We observed an inverse association between cumulative exposure to abdominal fat and arterial stiffness in older adults. Survivor bias or the role of sarcopenia may explain these findings.The association of fat deposits with subclinical vascular disease in older adults deserves careful evaluation. Estimation of long-term exposure to abdominal obesity did not reveal associations with arterial stiffness beyond a cross-sectional assessment of abdominal obesity.