Background: Pediatric obesity is a health epidemic. The function of adipocytes is determined by location and fat content (white vs. brown fat). In adults, periaortic fat is associated with cardiometabolic disease. However, very little is known about periaortic fat and its association with cardiometabolic disease in children.
Objective: Using free-breathing magnetic resonance imaging (MRI), this study aimed to: 1. measure periaortic fat volume and content and 2. investigate correlations between periaortic fat and clinical characteristics in children.
Methods: Healthy and overweight (body mass index ³ 85th percentile) children were eligible. Periaortic adipose tissue volume and proton-density fat fraction (PDFF), a biomarker for adiposity content, were measured in the abdominal aorta using free-breathing MRI.
Results: Healthy children (n=9, median age 10.8 (IQR 9.6-13.5) and overweight children (n=9, age 15.2 (12.7-16.0) completed the study. In comparison to healthy children (n= 9), median (IQR) periaortic adipose tissue volume in the abdominal aorta was significantly greater in overweight children (n=9) (5.3 cm3 (4.8-6.9) vs. 3.2 cm3 (2.9-3.7), p<0.0003). Likewise, periaortic adipose tissue PDFF was significantly greater in overweight children vs. healthy children (53% (50-55) vs. 31% (29-32), p<0.0001). Adipose tissue volume and PDFF were correlated with body mass index z-score (r=0.84 and r=0.89, P<0.001 each). In contrast, adipose tissue volume was negatively correlated with serum high density lipoprotein (r= -0.83, P<0.01).
Conclusion: In this study, overweight children had increased periaortic fat volume and PDFF compared to their healthy counterparts. A higher fat content (i.e., PDFF) may indicate a decrease in brown fat and increased susceptibility to future cardiometabolic disease.