Moderating effect of bone maturation on the relationship between body fat and insulin resistance.

Objectives: The aim of the present study was to analyze the moderating effect of maturation on the relationship between body fat and insulin resistance, in children from 9 to 12 years.

Methods: Maturity offset, homeostasis model assessment index of insulin resistance (HOMA-IR), and body fat percentage (BF%) were estimated in 127 children. Skeletal maturation indicator (SMI) was estimated in 105 participants. A moderation analysis based on a linear regression and on Johnson-Neyman technique was performed using a 95% confidence level.

Results: BF%, insulin levels, and HOMA-IR values were lower in late maturers than on-time maturers (p<0.05). SMI moderated the relationship between BF% and HOMA-IR index in 11.1% of boys and in 32.5% of girls (p<0.05). Also, the highest values of HOMA-IR index were observed at -1 year to achieve the peak height velocity, in girls (p<0.05).

Conclusions: Maturation process has a moderation effect on the relationship BF% and insulin resistance, particularly in early maturers; furthermore, it was independently associated with HOMA-IR.