IGF1 and vitamin D deficiency: Multivariate analysis revealed that the serum 25(OH)D level was an independent factor that could affect the risk of ICPP, which could be explained by the following: 1) Vitamin D deficiency was associated with an increased risk of adiposity, which could cause accelerated sexual maturation;27, 28, 29 2) Serum 25(OH)D levels are inversely related to leptin concentrations, which could affect the progression of early puberty;30,31 and 3) IGF-I could stimulate the gonadotropin-releasing hormone pulse, thereby affecting the onset of puberty.32