The effects of changes in body mass and subcutaneous fat on the improvement in metabolic risk factors in obese children after short-term weight loss.

The pattern of subcutaneous fat (SAT) is related to metabolic risk factors in obese children. Because weight loss improves the risk-factor profile, we sought to determine whether changes in SAT or SAT-pattern contribute to the improvement in the risk-factor profile after 3 weeks of a low-calorie diet and physical activities. In 22 obese boys (mean age, 11.9 years) and 40 obese girls (mean age, 12 years), fat mass (by means of impedance) and fat distribution (waist and hip circumference) were assessed. The thickness of 15 different subcutaneous adipose tissue layers (SAT-layers) was measured using a Lipometer (Moeller Messtechnik, Graz, Austria). SAT and SAT-pattern (arm-SAT, trunk-SAT, leg-SAT) were calculated. Blood samples were taken for the determination of insulin, glucose, triglycerides, and cholesterol. After 3 weeks, fat mass, waist and hip circumference, SAT, arm-SAT, trunk-SAT (all P <.0001), and leg-SAT (P <.01) were reduced. Besides glucose, metabolic parameters were lowered (all P <.001) but changes in metabolic parameter were interrelated in boys and girls. Age- and sex-adjusted regression revealed that changes in body mass contributed to the variability in changes of insulin (adjusted R(2) =.15, P =.0015). For the change in triglycerides, changes in cholesterol together with subtle alterations in glucose and changes in leg-SAT were found to be the main determinants (adjusted R(2) =.587, P <.0001). The results indicate that the change in the atherogenic and metabolic risk factor profile is largely independent from the concomitant loss in SAT. The reduction in body mass explained only a small part of the variability in changes of insulin, but leg-SAT might participate in the lowering of triglycerides, especially in boys. The contribution of SAT-pattern to the risk factor profile is an issue that needs further investigation.