Increased risk for development of coronary artery calcification in insulin-resistant subjects who developed diabetes: 4-year longitudinal study

Objective Coronary artery calcification (CAC) is considered a surrogate marker for atherosclerotic burden. The aim of this study was to analyze the risk of incident CAC associated with diabetes development in non-diabetic subjects with zero CAC score (CACS) at baseline. Methods 2076 non-diabetic participants (mean age 40 years) in a health screening program in whom CACS were repeatedly measured by multi-detector computed tomography in four years of intervals and with zero CACS at baseline, were retrospectively analyzed. Glycemic status was assessed in both years, with subjects divided into three groups: subjects with ‘no progression’, ‘normal to impaired fasting glucose (IFG)’ and ‘progression to diabetes’. Insulin resistance was assessed by homeostasis model assessment-insulin resistance (HOMA-IR) index. Results Over 4 years, 204 subjects (9.8%) developed CAC. Subjects who developed diabetes showed the highest proportion of subjects with incident CAC among the three groups (21.0% vs. 9.3 and 10.4% in non-progressors and subjects from normal to IFG). The subjects with HOMA-IR level in higher half at baseline showed significantly increased risk for incident CAC in subjects who progressed from normal to IFG and in subjects who developed diabetes (1.740; 95% CI 1.014–2.985, 2.449; 95% CI 1.159–5.174) even after adjustment for confounding variables, whereas subjects with HOMA-IR level in lower half at baseline showed no significantly increased risk for incident CAC even in subjects who developed diabetes. Conclusions In this non-diabetic population, we found that increased risk for incident CAC in relation to diabetes development over 4 years was pronounced only in subjects with insulin resistance at baseline.