The Relationship between Body Compositions and Serum Vitamin D Levels in Obese Adolescents

Purpose: Obesity and vitamin D deficiency is a significant public health problem with increasing frequency in childhood. Although numerous studies explored the correlation between obesity and vitamin D, the study is aimed to investigate such relationship in consideration of few/no studies on vitamin D and body compositions in obese people. Methods: A total of 62 adolescents aged 12 to 18 were included in the study, comprising 33 obese adolescents and 29 with normal weight. Blood samples were analyzed for 25-hydroxyvitamin D (25(OH)D), calcium (Ca), phosphorus (P), magnesium (Mg), alkaline phosphatase (ALP), parathyroid hormone (PTH), insulin, C-reactive protein (CRP), total cholesterol, LDL cholesterol (LDL), triglycerides (TG), and HDL cholesterol (HDL). Body fluid status and composition were assessed using bioimpedance spectroscopy (BIS) for both the obese and control groups. Results: Total body water (TBW), extracellular water (ECW), intracellular water (ICW), ECW/ICW (E/I) ratio, lean tissue index (LTI), adipose tissue index (FTI), lean tissue mass (LTM), adipose tissue mass (ATM), body cell mass (BCM) values were significantly higher in the obese group in comparison with the control group (p ˂ 0.05). There was no significant difference in 25(OH)D levels in the obese and control groups (p ˃ 0.05). The distribution of 25(OH)D values below and above 20 did not differ significantly in the obese and control groups (p ˃ 0.05). Cholesterol, insulin and HOMA-IR values were detected significantly higher in the obese group than in the control group (p ˂ 0.05). HDL and Ca values were significantly lower in the obese group than in the control group (p ˂ 0.05). A significant positive correlation was discovered between BMI value and TBW, ECW, ICW, E/I, LTI, FTI, LTM, ATM, BCM values (p ˂ 0.05). A significant positive correlation was discovered between HOMA IR value and TBW, ECW, ICW, E/I, FTI, FAT, ATM values (p< 0.05). No significant correlation was encountered between ....