Accuracy of Tri-ponderal Mass Index and Body Mass Index in Estimating Insulin Resistance, Hyperlipidemia, Impaired Liver Enzymes or Thyroid Hormone Functions and Vitamin D Level in Children and Adolescents

Objective: Tri-ponderal mass index (TMI) has been reported to estimate body fat more accurately than body mass index (BMI). This study aimed to compare the efficacy of TMI and BMI in forecasting of insulin resistance, hyperlipidemia, impaired liver enzymes or thyroid hormone functions and vitamin D level.

Method: One hundred and forty-three overweight or obese children according to standardised BMI (BMI SDS) were studied retrospectively. TMI thresholds to diagnose overweight status were 16.0 kg/m3 for boys, 16.8 kg/m3 for girls and to diagnose obese status were 18.8 kg/m3 for boys, 19.7 kg/m3 for girls.

Results: Twenty-two overweight and 8 obese children were classified as normal when TMI was used. These 22 overweight children had 22.7% insulin resistance and insulin resistance was detected in 2 of 8 obese children with normal TMI. There was no increase in liver enzymes of any children with normal TMI. Forty-four obese children were overweight according to TMI and insulin resistance were detected in of 40.9%. Thyrotrophinstimulating hormone were significantly higher in BMI obese when TMI classification did not effect the mean values of thyroid hormones. Vitamin D levels were same in all groups of both classifications.

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.