RELATION OF AORTIC STIFFNESS TO FACTORS MODIFYING THE RISK OF ATHEROSCLEROSIS IN HEALTHY PEOPLE

To identify factors predicting aortic stiffness, we studied the modulu s of elasticity of the thoracic aorta in relation to sex, obesity, blo od pressure, physical activity, smoking, ethanol consumption, salt int ake, and serum lipid and insulin levels in 55 healthy people born in 1 954. A transverse cine magnetic resonance image of the thoracic aorta was made, and the modulus of elasticity was determined as brachial art ery cuff pulse pressure/aortic strain, where strain was determined as the ratio of pulsatile aortic luminal area change to the diastolic lum inal area. The average of measurements made in the ascending and desce nding aorta was used as the elastic modulus of the thoracic aorta. Hab itual physical activity, smoking, and alcohol use were quantified by 2 -month prospective daily recording and salt intake by 7-day food recor ds. The aortic elastic modulus ranged from 100 to 2091 10(3) dyne/cm(2 ) (median, 390 10(3) dyne/cm(2)). In multiple regression analyses, log (10) aortic elastic modulus was related directly to mean blood pressur e (standardized coefficient [beta]=.37, P=.002), serum high-density li poprotein cholesterol (beta=.36, P=.012), square root of daily energy expenditure in physical activity (beta=.33, P=.005), and log(10) serum insulin (beta=.27, P=.047) and inversely to serum low-density lipopro tein cholesterol (beta=-.26, P=.035). A relation to salt intake was al so observed, but the regression slope was dependent on mean blood pres sure (P=.005 for interaction). These data suggest that many modifiable constitutional and lifestyle characteristics may contribute to the st iffness of the thoracic aorta.