The relationship between insulin resistance and incidence and progression of coronary artery calcification: the Multi-Ethnic Study of Atherosclerosis (MESA).

<bold>Objective: </bold>We sought to determine whether insulin resistance predicts the incidence and progression of coronary artery calcification (CAC).<bold>Research Design and Methods: </bold>We studied 5,464 participants not on hypoglycemic therapy from the Multi-Ethnic Study of Atherosclerosis (MESA). Each had baseline homeostasis model assessment of insulin resistance (HOMA-IR) and baseline and follow-up CAC scores. Incident CAC was defined as newly detectable CAC; progression was defined as advancing CAC volume score at follow-up.<bold>Results: </bold>Median HOMA-IR was 1.2 (0.8-2.0). Across all ethnicities, there was a graded increase in CAC incidence and progression with increasing HOMA-IR. When compared with those in the 1st quartile, participants in the 2nd-4th quartiles had 1.2, 1.5, and 1.8 times greater risk of developing CAC. Median annualized CAC score progression was 8, 14, and 17 higher, respectively. However, HOMA-IR was not predictive after adjustment for metabolic syndrome components.<bold>Conclusions: </bold>HOMA-IR predicts CAC incidence and progression, but not independently of metabolic syndrome. [ABSTRACT FROM AUTHOR]