ESPE Abstracts

Background: Evidence of the association between vitamin D, insulin resistance and oral disposition index (oDI) in obese children and adolescents is limited.

Objective and hypotheses: We investigated serum 25(OH)D levels in obese children and adolescents in Zhejiang, China, and determined the relationship between serum 25(OH)D and glucose metabolism.

Method: A cross-sectional design was used. All together 348 obese and 445 non-obese children and adolescents (aged from 6 to 16 years old) were enrolled in this study. Obese children were divided into four subgroups: normal glucose tolerance (NGT), isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), combined IFG and ITG (IFG+ITG) according to the oral glucose tolerance test. We measured serum 25(OH)D levels and calculated the homeostasis model of insulin resistance (HOMA-IR), the whole body insulin sensitivity index (WBISI), the product of β-cell function and insulin sensitivity by the disposition index (DI).

Results: The levels of 25(OH)D in obese group were significantly lower than those of non-obese group; serum 25(OH)D level in obese with NGT group was higher than that of the other three subgroups, and it was significantly inversed with LogHOMA-IR (r=−0.114, P=0.035), positively correlated with LogWBISI, LogHOMA₀DI after control for age, sex, season, puberty stage (r=0.111, P=0.040; r=0.122, P=0.024). Obese patients with vitamin D deficiency have a significantly higher risk of disturbing the glucose metabolism, such as IFG, ITG, IFG plus ITG, either IFG or ITG, for its OR 3.198 (95%CI 1.467–6.97), 5.443 (95%CI 1.863–15.897), 5.560 (95%CI 1.212–25.502), 4.007 (95%CI 2.017–7.962).

Conclusion: 25(OH)D deficiencies or insufficiency are common in obese children and adolescents in Zhejiang, China. Obese patients with 25(OH)D deficiency (<30 nmol/l) are at higher risk for abnormal glucose metabolism.