Visceral fat, insulin sensitivity, and lipids in prepubertal children

In adults, visceral fat accumulation is associated with insulin resistance and dyslipidemia. The cause-and-effect nature of these relationships is not clear. The objective of the present study was to determine if similar rela tionships exist in prepubertal children. Specifically, we determined whethe r visceral fat was associated with fasting insulin, insulin sensitivity (Si ), serum triglyceride (TG) concentration, or serum HDL cholesterol (HDL-C) concentration; whether visceral fat or Si was independently related to lipi ds; and whether ethnicity influenced the relationship between visceral fat and risk factors. Subjects were 61 prepubertal African-American and Caucasi an children. Total body fat was determined by dual-energy X-ray absorptiome try, visceral fat by computed tomography, and insulin sensitivity by the to lbutamide-modified, frequently sampled intravenous glucose tolerance test w ith minimal modeling. In multiple linear regression analysis (adjusting for total fat, sex, and ethnicity), visceral fat was independently related to TG (P < 0.05) and fasting insulin (P < 0.001), but not S-i (P = 0.425). Tot al body fat was independently related to Si (P < 0.001). Si was independent ly related to fasting insulin (P < 0.001) but not to TG or HDL-C (P = 0.941 and 0.201, respectively). S-i in African-Americans was 42% lower than in C aucasians (0.50 +/- 0.05 vs. 0.86 +/- 0.11 x 10(-5) min(-1).pmol(-1).l, mea n +/- SE after adjusting for total fat, P < 0.001). Nonetheless, ethnicity was not independently related to either TG or HDL-C (P = 0.075 and 0.619, r espectively, after adjusting for total and visceral fat and sex). The slope s of the relationships of total and visceral fat with risk factors did not differ with ethnicity. In conclusion, visceral fat appears metabolically un ique in children, being independently associated with elevated TG and insul in but not Si. Obese children and African-American children were more insul in resistant, independent of visceral fat accumulation. Lower Si was associ ated with higher, faster insulin, but not dyslipidemia. Thus, obesity, visc eral fat accumulation, and ethnicity in children may confer negative, but i ndependent, health risks.