ESPE Abstracts

Body mass index (BMI) is used to diagnose obesity in children and adolescents. Recently, the tri-ponderal mass index (TMI) has been reported to be nearly stable throughout adolescence and estimate body fat levels more accurately than BMI especially in adolescents. Aim: To compare the efficacy of TMI and BMI in forecasting of insulin resistance, hyperlipidemia and impaired liver enzymes.

Method: One hundred and forty-two overweight or obese children which were classified with BMI z-scores, were involved in the study. Children with BMI z-scores between +1.0 and +2.0 were overweight when children with BMD z-scores more than or equal to +2.0 were obese. BMI and TMI were calculated as weight(kg)/height(m2) and weight(kg)/height(m3), respectively. All anthropometric variables and laboratory results were collected retrospectively. The TMI thresholds to diagnose overweight status were 16.0 kg/m3 for boys, 16.8 kg/m3 for girls and were 18.8 kg/m3 for boys, 19.7 kg/m3 for girls to diagnose obese status. Fasting blood glucose, insulin, homeostasis model assessment insulin resistance (HOMA-IR), high (HDL) and low density (LDL) lipoprotein cholesterol, triglycerides, total cholesterol and liver function enzymes were evaluated. The HOMA-IR thresholds of Turkish children were used to diagnose insulin resistance (2.22 for prepubertal girls, 2.67 for prepubertal boys, 3.82 pubertal girls, 5.22 for pubertal boys).

Results: Twenty-two overweight and 8 obese children were classified as normal when we used the TMI. Twenty-two overweight children with normal TMI had 22.7% insulin resistance, 9.1% high total cholesterol level, 4.5% low HDL and high triglyceride level and 50% higher LDL levels than 100 mg/dL. Two of 8 obese children with normal TMI had insulin resistance and low HDL levels. There was no incerase in liver enzyme levels in any child with normal TMI. Forty-four obese children were classified as overweight according to the TMI. In this group, insulin resistance were detected in of 40.9%, low HDL in 34.1% and at least one of elevated liver enzyme in 11.4%. Fifty-four patients were obese according to the both BMI z score and TMI.

Conclusion: In conclusion, when we use TMI, we may have a risk of skip over the insulin resistance. However, if we assume that liver enzymes are elevated as a finding of visceral adiposity, TMI can be used as an auxiliary parameter to show visceral effects of adiposity. Normal TMI may indicate that visceral organ functions have not deteriorated yet.