The association of FGF23 levels in obese adolescents with insulin sensitivity

J Pediatr Endocrinol Metab. 2012;25(7-8):687-90. doi: 10.1515/jpem-2012-0064.

Abstract

Background: The fibroblast growth factor 23 (FGF23) is the most important hormonal regulator of circulating phosphate levels. Apart from this essential role, it may also act as a 'hormone-like' factor involved in glucose and lipid metabolism. It is believed to have a potential role in the development of insulin resistance.

Aim: The aim of the study was to compare FGF23 levels between two groups of obese adolescents: insulin resistant and non-insulin resistant.

Patients: The study included 36 obese, insulin-resistant adolescents (21 boys and 15 girls) of pubertal age (mean age, 13.95 years; Tanner stage IV or V). The control group consisted of 21 obese peers with normal HOMA-IR values.

Methods: FGF23 levels were measured in a fasting blood sample by Human Intact FGF-23 ELISA Kit (Immunotopics Inc., San Clemente, CA, USA). A standard oral glucose tolerance test was performed, which assessed fasting and 120 min postload plasma glucose and serum insulin levels; the insulin resistance index HOMA-IR was calculated. The definition of insulin resistance was based on a HOMA-IR threshold set for adolescents (> or = 3.16).

Results: There was a significant inverse correlation between FGF23 levels and HOMA-IR (R = -0.26, p < 0.05) in the study group. FGF23 levels were also significantly lower in the study group (9.8 vs. 11.9 pg/mL, p = 0.026).

Conclusions: In adolescents with simple obesity and insulin resistance, FGF23 levels are lower compared with obese adolescents with normal HOMA-IR.

MeSH terms

  • Adolescent
  • Age of Onset
  • Blood Glucose / metabolism
  • Blood Pressure / physiology
  • Body Composition / physiology
  • Case-Control Studies
  • Child
  • Cholesterol / blood
  • Female
  • Fibroblast Growth Factors / blood*
  • Humans
  • Insulin Resistance / physiology*
  • Male
  • Obesity / blood*
  • Obesity / epidemiology
  • Obesity / metabolism
  • Obesity / physiopathology

Substances

  • Blood Glucose
  • Fibroblast Growth Factors
  • fibroblast growth factor 23
  • Cholesterol