Favorable Fatty Acid Composition in Adipose Tissue in Healthy Iraqi- Compared to Swedish-Born Men Assessed by MRI

Background: Middle Eastern immigrants are at high-risk for insulin resistance. Fatty acid composition (FAC) plays an important role in the development of insulin resistance but has not been investigated in people of Middle Eastern ancestry. Here, the aim was to assess the FAC in visceral and subcutaneous adipose tissue (VAT and SAT) in healthy Iraqi- and Swedish-born men using a magnetic resonance imaging (MRI) method. Methods: This case-control study included 23 Iraqi- and 15 Swedish-born middle-aged men, without cardiometabolic disease. Using multi-echo MRI of the abdomen, the fractions of saturated, monounsaturated, and polyunsaturated fatty acids (fSFA,f MUFA , and fPUFA , respectively) were estimated in VAT and SAT. SAT was further analyzed in deep and superficial compartments (dSAT and sSAT). Findings: In all investigated adipose tissue depots, fPUFA was significantly higher (p <0.001) and f significantly lower (p <0.001) in Iraqi men, independently of age and BMI. In both Iraqi- and Swedish-born men, higher fPUFA and lower fMUFA were found in sSAT vs. dSAT. Among Iraqi men only, higher f PUFA and lower f MUFA were found in SAT vs. VAT (p <0.001). Interpretations: Iraqi-born men presented a more favorable abdominal adipose tissue FAC compared to Swedish-born men. This MRI method also revealed differences in FAC comparing different abdominal adipose tissue depots. Our results may reflect a beneficial FAC in Middle Eastern immigrants which needs to be further investigated. Funding: Lund University; the Swedish Research Council; the Swedish Foundation for Strategic Research; MAS Foundation for Fighting Cancer; the Cancer Research Foundation, Oncology Department, SUS Malmo. Declaration of Interest: None to declare. Ethical Approval: Approval for the study was granted from the Ethical Review Board of Lund University (2015/507).