The use of urinary Insulin-like Growth Factor-I (IGF-I) for determining skeletal age of participants

Introduction: Biochemical markers play an important role in the growth and repair of bone and can be evaluated in different biological fluids. Therefore, the aim of this study was to evaluate the level of insulin-like growth factor-I (IGF-I) in urine as a puberty index and to compare it with cervical vertebral maturational stages (CVMSs) in lateral cephalometry. Materials&Methods: In this cross-sectional study, 50 8-18-year-old patients (males and females), referred to Faculty of Dentistry with CVMS of 2 to 6 and needed orthodontic treatment as well as lateral cephalometry were selected. All of these patients were healthy. The CVMSs were recorded based on lateral cephalometric radiographs and urinary levels of IGF-I was determined using a urine-based ELISA kit. Mean IGF-I values for each CVMS were analyzed by Mann-Whitney, Kruskal-Wallis and Chi-square tests in SPSS. P<0.05 was statistically considered as significant level. Results: In this study, the mean age of participants, ranged from 8 to 18 years was 12.96±3.82. There was no statistically significant difference in gender distribution between CVM groups (P=0.106). The level of urinary IGF-I had no significant difference between groups, except for CVMS3 group (P=0.073). In CS3, the mean urinary IGF-I level was 0.2727, representing a significant difference from other groups (P=0.000). IGF-I levels had no significant differences between males (0.03±0.04) and females (0.08±0.011), (P=0.492). Conclusion: The highest urinary IGF-I level was found in both genders in CVMS 3 and 4, which coincided with peak growth spurt in patients.