A prospective study of abdominal obesity and coronary artery calcium progression in older adults.

OBJECTIVE: Little is known about obesity measurements and coronary artery calcium (CAC) progression in older adults. We examined the sex-specific association between measures of body size and fat distribution with CAC progression.

SUBJECTS AND METHODS: Participants were 156 men and 182 women (mean age 67 yr) without known heart disease who had electron-beam computed tomography for CAC at baseline and again 4.5 yr later. Obesity assessments were weight, height, body mass index, waist and hip circumference, waist to hip ratio, waist to height ratio, sc and visceral adipose tissue (SAT, VAT), and SAT to VAT ratio based on abdominal electron-beam computed tomography. CAC progression was defined as categorical (square root increased on total CAC volume score > or = 2.5 mm(3)) and continuous variables.

RESULTS: During the follow-up, 55% of men and 38.5% of women had CAC progression. Increased waist to hip ratio (> or = 0.9 for men, > or = 0.85 for women) and waist to height ratio (> or = 0.55 for men, > or = 0.54 for women) were positively and independently associated with CAC progression [median (interquartile range)] [60.8 (145) vs. 10.8 (56) mm(3), P = 0.002 and 50 (153) vs. 22(84) mm(3), P = 0.03, respectively]. In women but not men, an increased waist circumference (> 88 cm) independently predicted CAC progression (odds ratio 3.0 95% confidence interval 1.03-8.0, P = 0.04), whereas VAT to SAT ratio predicted CAC progression in men but not women (odds ratio 2.8 95% confidence interval 1.01-7.8, P = 0.04).

CONCLUSION: In this study of older adults without known heart disease, abdominal obesity was an independent predictor of CAC progression. These results point to the importance of using clinical measurements of abdominal obesity to identify individuals at increased risk for atherosclerosis.