[Body mass index, tri-ponderal mass index, and pubertal growth pattern. New data in a Spanish population]

[Growth hormone deficit: Influence of puberty on the response to treatment]

INTRODUCTION

Short stature is the most frequent reason for consultation in Pediatric Endocrinology consultations and sometimes requires treatment with growth hormone. The aim of the study was to analyze the response to treatment based on its onset in pubertal or prepubertal stages and to analyze the possible benefit of an early onset.

PATIENTS AND METHODS

Longitudinal, retrospective and observational study in 139 patients treated for idiopathic growth hormone deficiency up to adult height.

MAIN VARIABLES STUDIED

(a) genetic background: maternal, paternal and genetic height; (b) perinatal history; (c) anthropometry during follow-up and at pubertal onset: weight, height, body mass index; (d) variables during follow-up and at pubertal onset: growth rate, bone age and growth prognosis. Final response variables: adult height, adult height with respect to target height, adult height with respect to initial growth prediction, adult height with respect to initial height at the start of treatment and adult height with respect to height at pubertal onset.

RESULTS

Total pubertal gain was 0.84±0.6 SD. 61.9% of the patients started treatment with rhGH in prepuberty. The initiation of treatment in the prepubertal stage and a higher total pubertal gain are correlated with a better final height (P=.001 and r=0.507, P=.00, respectively). Furthermore, a longer duration of treatment in pre-puberty is correlated with a better final response (r=0.328, P=.00).

CONCLUSIONS

The start of treatment in the prepubertal stage and its longer duration during this period are determining factors to achieve a good long-term response. Total pubertal gain was greater in patients who started treatment in the pubertal stage.

Accuracy of Tri-ponderal Mass Index and Body Mass Index in Estimating Insulin Resistance, Hyperlipidemia, Impaired Liver Enzymes or Thyroid Hormone Function and Vitamin D Levels 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 predicting insulin resistance (IR), hyperlipidemia, impaired liver enzymes or thyroid hormone function and vitamin D concentration.

METHODS

One hundred and forty-three overweight or obese children, based on BMI-standard deviation (SD) scoring (BMI-SDS) were studied retrospectively. TMI thresholds for overweight status were 16.0 kg/m³ for boys and 16.8 kg/m³ for girls and 18.8 kg/m³ for boys and 19.7 kg/m³ for girls for obese status.

RESULTS

Twenty-two overweight and eight obese children by BMI-SDS were classified as normal by TMI. Of the overweight children 22 (22.7%) had IR and IR was detected in 2 of 8 obese children with normal TMI. There was no increase in liver enzymes in any of the children with normal TMI. Forty-four obese children were overweight according to TMI and IR was detected in 40.9%. Thyroid stimulating hormone levels were significantly higher in BMI-based obese children. Vitamin D levels were similar in all groups of both classifications.

CONCLUSION

When TMI was used there may be a risk of overlooking IR. However, if it is assumed that liver enzymes are elevated as a result 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. More studies are needed to evaluate TMI as a clinical tool.