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.
27 - 29 Sep 2018
European Society for Paediatric Endocrinology