Relationship of Left Ventricular Mass to Lean Body Mass in the Obese Pediatric Population

Our primary aim was to investigate the relationship between LVM and anthropometric measures including lean body mass (LBM) in obese pediatric subjects compared to normal weight controls. A retrospective chart review identified subjects 2-18 years old who were normotensive and had normal echocardiograms between 1995 and 2020 at Boston Children's Hospital. LVM was calculated with the 5/6 area length rule from 2D echocardiograms. LBM was calculated with equations derived from dual-energy X-ray absorptiometry. Of the 2217 subjects who met inclusion criteria, 203 were obese and 2014 had normal weight. The median age was 11.9 (2.0-18.9); 46% were female. The median LVM was 94.5 g (59.3-134.3) in obese subjects vs. 78.0 g (51.5-107.7) in controls. The median LBM was 37.2 kg (18.9-50.6) in obese subjects vs. 30.5 kg (17.6-40.8) in controls. In control and obese subjects, LBM had the strongest correlation to LVM (R² 0.86, P < 0.001) and (R² 0.87, P < 0.001), respectively. There was at most a modest correlation between tissue Doppler velocity z-scores and LV mass, and the largest was Septal E' z-score in obese subjects (r = - 0.31, P = 0.006). In this cohort, LBM was found to have the strongest relationship to LVM in obese subjects. The largest correlation between tissue Doppler velocity z-scores and LV mass was Septal E' z-score. Future studies will evaluate which measurements are more closely aligned with clinical outcomes in obese children.