The relationship between insulin resistance and vascular calcification in coronary arteries, and the thoracic and abdominal aorta: the Multi-Ethnic Study of Atherosclerosis.

OBJECTIVE: Insulin resistance may be related to vascular calcification as both are associated with abdominal obesity. We investigated the association of insulin resistance with abdominal aortic calcium (AAC), coronary artery calcium (CAC) and thoracic aortic calcium (TAC), and whether it differs according to different levels of subcutaneous fat area (SFA) and visceral fat area (VFA) in a cross-sectional study design.

METHODS: We investigated 1632 participants without diabetes from the Multi-Ethnic Study of Atherosclerosis with valid data on homeostasis model assessment index (HOMA-IR), AAC, CAC, and TAC. Adipocytokines, SFA, and VFA were also determined.

RESULTS: HOMA-IR was associated with the presence of CAC, but not AAC and TAC, and the association remained significant after adjusting for traditional risk factors, adipocytokines, abdominal muscle mass, SFA, and VFA (prevalence ratio = 1.04 per one interquartile range [IQR] increase, P = 0.01). As the strength of the association of HOMA-IR with vascular calcification may differ by abdominal fat composition, subgroup analysis was performed among participants with different tertiles of SFA and VFA. Significant interactions between HOMA-IR with SFA and VFA separately were observed for the presence of TAC, but not AAC and CAC, even after adjusting for confounding factors. The association of HOMA-IR with TAC tended to be stronger in participants with more SFA and VFA.

CONCLUSIONS: Atherosclerotic calcification, especially in the coronary arteries, is related to insulin resistance. Further studies are needed to delineate the mechanisms by which visceral obesity can lead to vascular calcification.