1699-P: Association between Insulin Resistance and Myosteatosis Measured by Abdominal Computed Tomography

Background: Ectopic fat deposition in skeletal muscle, termed myosteatosis, is a key factor in developing insulin resistance. We aimed to evaluate the association between insulin resistance and myosteatosis in a large Asian population. Methods: A total of 18,251 participants who had abdominal computed tomography from 2012 to 2013 were included. The total abdominal muscle area (TAMA) at the L3 vertebral level was segmented into normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA), and intramuscular adipose tissue (IMAT). The ratios of NAMA/BMI, LAMA/BMI, and NAMA/TAMA were used as myosteatosis indices. Results: NAMA/BMI and NAMA/TAMA index showed downward trends with higher HOMA-IR levels, while LAMA/BMI showed upward trends. As HOMA-IR levels increased, the odds ratios (ORs) of the highest quartile of NAMA/BMI and NAMA/TAMA index decreased and that of LAMA/BMI increased. Compared with the lowest HOMA-IR group, the adjusted ORs (95% confidence intervals [CI]) in the highest HOMA-IR group for the lowest NAMA/TAMA quartile were 0.414 (0.364-0.471) in males and 0.464 (0.384-0.562) in females. HOMA-IR showed a negative correlation with NAMA/TAMA index (r = -0.211 for men and r = -0.214 for women, p <0.001 for both). Conclusion: A higher HOMA-IR level was significantly associated with a high risk of myosteatosis. Disclosure M.Kim: None. Y.Cho: None. H.Jung: None. C.Jung: None. J.Won: None. J.Park: None. H.Kim: None. W.Lee: None.