FGF23 contributes to insulin sensitivity in obese adolescents - preliminary results

Fibroblast growth factor-23 (FGF23) is a hormonal regulator of circulating phosphate and vitamin D levels. Recent investigations revealed that besides a key role in the pathogenesis of calcium-phosphorus disorders, in some patients FGF23 may be an indicator of cardiovascular complications. As a 'hormone-like' factor, it may also be involved in some metabolic processes, especially in the metabolism of glucose and fat. Its potential contribution to metabolic syndrome (MS) development has not been confirmed yet.

The study was to examine the possible correlations between FGF23 serum levels and body composition, blood pressure and selected parameters of glucose, insulin and fat metabolism in adolescents with simple obesity.

In 68 (35 female) adolescents (mean age 13·9 years) with simple obesity [mean BMI SDS 4·9 (95% CI 4·4-5·4)], the levels of FGF23, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides were measured. Standard oral glucose tolerance tests were performed with the assessment of fasting and after 120' postload glucose and insulin levels; the insulin resistance index HOMA-IR was calculated.

Regardless of gender, there was a significant inverse correlation between FGF23 and fasting insulin level (r = -0·3), as well as HOMA-IR (r = -0·29). Multiple regression model showed the independent association between FGF23 and HOMA-IR.

FGF23 seems to be a novel factor contributing to insulin sensitivity. Further investigations are needed to define its role in the development of MS.