The relation of vitamin D deficiency with puberty and insulin resistance in obese children and adolescents.

The prevalence of obesity among children and adolescents has been rapidly increasing in recent years. Obese individuals are at risk for vitamin D deficiency. The aim of this study was to investigate the relation of vitamin D deficiency with puberty and insulin resistance in obese children and adolescents. A total of 106 children and adolescents (48 prepubertal and 58 pubertal) between 8 and 16 years of age were included in the study. Fasting blood glucose, insulin, lipid profile, calcium, phosphorus, alkaline phosphatase, parathyroid hormone, 25-hydroxyvitamin D [25(OH)D] levels, as well as blood glucose and insulin concentrations at 120 min of oral glucose tolerance test were measured. Insulin resistance was calculated using the homeostasis model assessment. Daily vitamin D intake was questioned. Serum 25(OH)D level was normal in only 3.8%, insufficient in 34.0%, and deficient in 62.2% of the subjects. There was a statistically significant rate of 25(OH)D deficiency in the pubertal group compared with that in the prepubertal group. Those subjects with 25(OH)D deficiency were found to have greater insulin resistance. Vitamin D deficiency is common among obese children and adolescents. Low vitamin D levels in obese individuals may accelerate the development of metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease by further increasing insulin resistance.