Ectopic and Serum Lipid Levels Are Positively Associated with Bone Marrow Fat in Obesity

Purpose: To investigate the associations between ectopic and serum lipid levels and bone marrow fat, as a marker of stem cell differentiation, in young obese men and women, with the hypothesis that ectopic and serum lipid levels would be positively associated with bone marrow fat. Materials and Methods: The study was institutional review board approved and complied with HIPAA guidelines. Written informed consent was obtained. The study group comprised 106 healthy young men and women (mean age, 33.7 years +/- 6.8 [standard deviation]; range, 19-45 years; mean body mass index (BMI), 33.1 kg/m(2) +/- 7.1; range, 18.1-48.8 kg/m(2)) who underwent hydrogen 1(1H) magnetic resonance (MR) spectroscopy by using a point-resolved spatially localized spectroscopy sequence at 3.0 T of L4 for bone marrow fat content, of soleus muscle for intramyocellular lipids (IMCL), and liver for intrahepatic lipids (IHL), serum cholesterol level, serum triglyceride level, and measures of insulin resistance (IR). Exercise status was assessed with the Paffenbarger activity questionnaire. Results: There was a positive correlation between bone marrow fat and IHL (r = 0.21, P = .048), IMCL (r = 0.27, P = .02), and serum triglyceride level (r = 0.33, P = .001), independent of BMI, age, IR, and exercise status (P < .05). High-density lipoprotein cholesterol levels were inversely associated with bone marrow fat content, independent of BMI, age, IR, and exercise status (r = -0.21, P = .019). Conclusion: Results of this study suggest that ectopic and serum lipid levels are positively associated with bone marrow fat in obese men and women. (C)RSNA, 2013