RELATIONSHIP OF AGE, GENDER, RACE, AND BODY-SIZE TO INFRARENAL AORTICDIAMETER

Purpose: To assess the effects of age, gender, race, and body size on infrarenal aortic diameter (IAD) and to determine expected values for IAD on the basis of these factors. Methods: Veterans aged 50 to 79 yea rs at 15 Department of Veterans Affairs medical centers were invited t o undergo ultrasound measurement of IAD and complete a prescreening qu estionnaire. We report here on 69,905 subjects who had no previous his tory of abdominal aortic aneurysm (AAA) and no ultrasound evidence of AAA (defined as IAD greater than or equal to 3.0 cm). Results: Althoug h age, gender, black race, height, weight, body mass index, and body s urface area were associated with IAD by multivariate linear regression (all p < 0.001), the effects were small. Female sex was associated wi th a 0.14 cm reduction in IAD and black race with a 0.01 cm increase i n IAD. A 0.1 cm change in IAD was associated with large changes in the independent variables: 29 years in age, 19 cm or 40 cm in height, 35 kg in weight, 11 kg/m(2) in body mass index, and 0.35 m(2) in body sur face area. Nearly all height-weight groups were within 0.1 cm of the g ender means, and the unadjusted gender means differed by only 0.23 cm. The variation among medical centers had more influence on IAD than di d the combination of age, gender, race, and body size. Conclusions: Ag e, gender, race, and body size have statistically significant but smal l effects on IAD. Use of these parameters to define AAA may not offer sufficient advantage over simpler definitions (such as an IAD greater than or equal to 3.0 cm) to be warranted.