Abdominal aortic calcium and multi-site atherosclerosis: The Multiethnic Study of Atherosclerosis

Background: Abdominal aortic calcification (AAC) is a measure of subclinical cardiovascular disease (CVD). Data are limited regarding its relation to other measures of atherosclerosis. Methods: Among 1812 subjects (49% female, 21% black, 14% Chinese, and 25% Hispanic) within the population-based Multiethnic Study of Atherosclerosis, we examined the cross-sectional relation of AAC with coronary artery calcium (CAC), ankle brachial index (ABI), and carotid intimal medial thickness (CIMT), as well as multiple measures of subclinical CVD. Results: AAC prevalence ranged from 34% in those aged 45-54 to 94% in those aged 75-84 (p< 0.0001), was highest in Caucasians (79%) and lowest in blacks (62%) (p< 0.0001). CAC prevalence, mean maximum CIMT ≥ 1. mm, and ABI < 0.9 was greater in those with vs. without AAC: CAC 60% vs. 16%, CIMT 38% vs. 7%, and ABI 5% vs. 1% for women and CAC 80% vs. 37%, CIMT 43% vs. 16%, and ABI 4% vs. 2% for men (p< 0.01 for all except p< 0.05 for ABI in men). The substantially greater prevalence for CAC in men compared to women all ages is not seen for AAC. By age 65, 97% of men and 91% of women have AAC, CAC, increased CIMT, and/or low ABI. The presence of multi-site atherosclerosis (≥3 of the above) ranged from 20% in women to 30% in men (p< 0.001), was highest in Caucasians (28%) and lowest in Chinese (16%) and ranged from 5% in those aged 45-54 to 53% in those aged 75-84 (p< 0.01 to p< 0.001). Finally, increased AAC was associated with 2-3-old relative risks for the presence of increased CIMT, low ABI, or CAC. Conclusions: AAC is associated with an increased likelihood of other vascular atherosclerosis. Its additive prognostic value to these other measures is of further interest.