The relationship of insulin resistance and extracoronary calcification in the multi-ethnic study of atherosclerosis

Objective: We hypothesized that insulin resistance, measured by the homeostasis model assessment of insulin resistance (HOMA), is independently associated with prevalent and incident extra-coronary calcification (ECC). Methods: We studied calcium scores of the aortic valve calcification (AVC), mitral valve calcification (MVC), thoracic aorta calcification (TAC) and aortic valve root calcification (AVR) in 6104 MESA participants not on diabetes medication who had baseline cardiac CT scans; 5312 had follow-up scans (mean 2.4 years). Relative-risk regression modeled prevalent and incident ECC adjusted for baseline demographics (model 1), and additionally for CVD risk factors (model 2). Results: In model 1, prevalence and incidence risk-ratios for the highest versus lowest quartile of HOMA were 20-30% higher in all ECC locations (. p-value for trend ≤0.05 for all but incident-AVC). In model 2, all associations were attenuated, primarily by adjustment for metabolic syndrome components. Conclusions: HOMA has a positive and graded association with ECC, but not independently of cardiovascular risk factors-particularly metabolic syndrome components.