|DE LAS HERAS, JAVIER - Hospital De Cruces|
|RAJAKUMAR, KUMARAVEL - University Of Pittsburgh Medical Center|
|LEE, SOJUNG - University Of Pittsburgh Medical Center|
|BACHA, FIDA - Children'S Nutrition Research Center (CNRC)|
|HOLICK, MICHAEL - Boston University Medical Center|
|ARSLANIAN, SILVA - University Of Pittsburgh Medical Center|
Submitted to: Diabetes Care
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2012
Publication Date: 7/1/2013
Citation: De Las Heras, J., Rajakumar, K., Lee, S., Bacha, F., Holick, M.F., Arslanian, S.A. 2013. 25-hydroxyvitamin D in obese youth across the spectrum of glucose tolerance from normal to prediabetes to type 2 diabetes. Diabetes Care. 36(7):2048-2053.
Interpretive Summary: Studies in adults have shown that low levels of vitamin D are related to a higher risk for type 2 diabetes. It is known that vitamin D levels are related to body fat and are lower in obese children. It is not clear if low vitamin D levels in children are related to measures of insulin action or secretion which are both important in determining the risk for type 2 diabetes. We evaluated the levels of vitamin D in 175 black and white children. Researchers also evaluated body fat, glucose and insulin metabolism. We found no differences in vitamin D levels among obese children with and without diabetes. There was also no relationship between the vitamin D levels and insulin secretion and action in these children. In conclusion, our study does not support a direct role of vitamin D in the risk for type 2 diabetes in children.
Technical Abstract: The objective of this study was to 1) determine if plasma 25-hydroxyvitamin D (25[OH]D) concentrations differ among obese youth with normal glucose tolerance (NGT) versus prediabetes versus type 2 diabetes and 2) assess the relationships between 25(OH)D and in vivo insulin sensitivity and Beta-cell function in this cohort. Plasma 25(OH)D concentrations were examined in banked specimens in 9- to 20-year-old obese youth (n = 175; male 42.3%, black 46.3%)(NGT, n = 105; impaired glucose tolerance [IGT], n = 43; type 2 diabetes, n = 27) who had in vivo insulin sensitivity and secretion measured by hyperinsulinemic-euglycemic and hyperglycemic clamp techniques and had an assessment of total body composition and abdominal adiposity. The mean age and BMI of the subjects were 14.3 +/- 2.1 years and 35.7 +/- 5.6 kg/m2, respectively. BMI, plasma 25(OH)D, and the proportion of vitamin D–deficient and –insufficient children did not differ across the three groups. Furthermore, there was no association between 25(OH)D and in vivo insulin sensitivity or Beta-cell function relative to insulin sensitivity (disposition index) in all groups combined or in each group separately. Our data in obese youth show 1) no differences in plasma 25(OH)D concentrations across the glucose tolerance groups and 2) no relationship between 25(OH)D and in vivo insulin sensitivity and Beta-cell function relative to insulin sensitivity in any of the groups. It remains uncertain if enhancement of the vitamin D status could improve pathophysiological mechanisms of prediabetes and type 2 diabetes in obese youth.