Growth of visceral fat, subcutaneous abdominal fat, and total body fat in children.

OBJECTIVE: To examine the patterns of growth of visceral fat, subcutaneous abdominal fat, and total body fat over a 3- to 5-year period in white and African American children. RESEARCH METHODS AND PROCEDURES: Children (mean age: 8.1 +/- 1.6 years at baseline) were recruited from Birmingham, Alabama, and those with three or more repeated annual measurements were included in the analysis (N = 138 children and 601 observations). Abdominal adipose tissue (visceral and subcutaneous) was measured using computed tomography. Total body fat and lean tissue mass were measured by DXA. Random growth curve modeling was performed to estimate growth rates of the different body fat compartments.
RESULTS: Visceral fat and total body fat both exhibited significant growth effects before and after adjusting for subcutaneous abdominal fat and lean tissue mass, respectively, and for gender, race, and baseline age (5.2 +/- 2.2 cm(2)/yr and 1.9 +/- 0.8 kg/yr, respectively). After adjusting for total body fat, the growth of subcutaneous abdominal fat was not significant. Whites showed a higher visceral fat growth than did African Americans (difference: 1.9 +/- 0.8 cm(2)/yr), but there was no ethnic difference for growth of subcutaneous abdominal fat or total body fat. There were no gender differences found for any of the growth rates. DISCUSSION: Growth of visceral fat remained significant after adjusting for growth of subcutaneous abdominal fat, implying that the acquisition of the two abdominal fat compartments may involve different physiologic mechanisms. In contrast, growth of subcutaneous abdominal fat was explained by growth in total body fat, suggesting that subcutaneous fat may not be preferentially deposited in the abdominal area during this phase of growth. Finally, significantly higher growth of visceral fat in white compared with African American children is consistent with cross-sectional findings.