Coronary artery calcification at electron beam computed tomography is increased in asymptomatic type 2 diabetics independent of traditional risk factors

Abstract

Background: The risk of cardiovascular disease (CVD) is two- to fourfold greater in type 2 diabetics than in non-diabetics and cannot be accounted for by traditional risk factors alone. Coronary artery calcification (CAC) at electron beam computed tomography (EBCT) is a non-invasive index of coronary atherosclerosis. We hypothesized that the presence and extent of CAC would be greater in asymptomatic type 2 diabetics than in non-diabetics independent of traditional risk factors.

Methods: We reviewed CAC data of all asymptomatic subjects referred for EBCT between 1996-1999 and compared CAC scores in type 2 diabetics ( n= 71) to all non-diabetics ( n= 1481) and to a randomly selected group of non-diabetics matched for all traditional CVD risk factors ( n= 71).

Results: CAC scores were greater in type 2 diabetics (272 +/- 472, median 41) than in all non-diabetics (104 +/- 288, median 4; < 0.01) and matched non-diabetics (188 +/- 354; < 0.05, median 12; < 0.05). The odds ratio (OR) for the presence of CAC (scores > 0) in type 2 diabetics was 2.9 [95% confidence intervals (CI) 1.1-7.8] after adjustment for traditional CVD risk factors. Type 2 diabetes was also associated (adjusted OR 2.15, 95%CI 1.3-3.6) with the extent of CAC when categorized as an ordinal outcome (CAC scores 0, 1-79, 80-399 and > 400). In type 2 diabetics, age, sex and body mass index were associated with extent of CAC.

Conclusions: CAC scores at EBCT are greater in type 2 diabetics than non-diabetic subjects, cannot be accounted for by traditional risk factors alone and may be useful for identifying novel factors for coronary atherosclerosis in type 2 diabetes.