Abstract MP58: Intermuscular Fat Density: Novel Risk Factor for Cardiometabolic Risk Factors in African-Ancestry Men

Abstract

Background: While overall obesity remains a major risk factor for cardiometabolic diseases, the location of stored fat is also thought to play a role. In addition to fat storage in ectopic sites, the density of fat, a marker of fat quality, is emerging as a novel risk factor for cardiometabolic diseases. Previous studies have focused primarily on visceral (VAT) and abdominal subcutaneous (SAT) adipose tissue density and in predominantly white cohorts; however, studies in populations of African ancestry who are at higher risk of cardiometabolic diseases are lacking. Additionally, information is lacking on associations of density of other relevant ectopic fat depots, such as intermuscular adipose tissue (IMAT), with cardiometabolic risk factors. Methods: We investigated whether VAT, SAT, or thigh IMAT densities were associated with cardiometabolic measures in 648 black men aged 50-91 years (mean age 63.6 years, mean BMI 27.7 kg/m 2 ). Adipose tissue volume (cm 3 ) and density (Hounsfield units, HU) was measured in the abdomen (between L4 and L5) and mid-thigh from computed tomography scans. Cardiometabolic measures, including blood pressure, fasting serum glucose and insulin homeostasis, and serum lipids (N=476), were transformed as needed and used as outcomes in multiple linear regression models adjusting for age, lifestyle factors, medication use (antihypertensive, antidiabetic, or lipid-lowering), and corresponding fat depot volume. Results: After adjustment (Table), VAT, SAT, and IMAT densities were significantly associated with fasting insulin, insulin resistance, and lipids. Results remain similar after adjustment for BMI instead of fat volume and in a sensitivity analysis excluding those taking relevant medications. Conclusion: As reported in other studies, in our study among African ancestry individuals VAT and SAT were associated with several cardio-metabolic risk factors. Importantly, our findings suggest that thigh IMAT density may be a novel predictor of cardiometabolic risk in African ancestry men.