CONTEXT: Vitamin D status can influence insulin resistance. OBJECTIVE: The aim of the study was to determine the prevalence of vitamin D deficiency in obese African-American (AA) adolescent females in a southeastern latitude and to determine the relationship of 25-hydroxyvitamin D [25(OH)D] with insulin and glucose dynamics. DESIGN: We conducted a cross-sectional study in a University Children's Hospital. METHODS: Serum 25(OH)D, fasting glucose, PTH, serum calcium, serum lipids, serum transaminases, and C-reactive protein were assessed. Indices of insulin sensitivity and resistance were determined from an oral glucose tolerance test. Subjects were classified as vitamin D deficient or sufficient, based on the traditional vitamin D deficiency definition [serum 25(OH)D <20 ng/ml] and also by a lower 25(OH)D cut-point of 15 ng/ml or less. RESULTS: A total of 51 AA adolescent females (body mass index, 43.3 +/- 9.9 kg/m(2); age, 14 +/- 2 yr) were studied. Serum 25(OH)D concentrations were 20 ng/ml or less in 78.4% and 15 ng/ml or less in 60.8% of subjects. There were no significant group differences in the metabolic outcomes when subjects were classified using the traditional vitamin D deficiency definition. The Matsuda index of insulin sensitivity was significantly lower (P = 0.02), and insulin area under the curve was significantly higher (P = 0.04) in subjects with 25(OH)D concentrations of 15 ng/ml or less vs. those with higher concentrations. CONCLUSIONS: Vitamin D deficiency is highly prevalent in obese, AA female adolescents and may promote insulin resistance. Our data suggest that a 25(OH)D concentration of 15 ng/ml or less may be the threshold by which vitamin D deficiency confers negative effects on insulin sensitivity.
CONTEXT: Vitamin D status can influence insulin resistance. OBJECTIVE: The aim of the study was to determine the prevalence of vitamin D deficiency in obese African-American (AA) adolescent females in a southeastern latitude and to determine the relationship of 25-hydroxyvitamin D [25(OH)D] with insulin and glucose dynamics. DESIGN: We conducted a cross-sectional study in a University Children's Hospital. METHODS: Serum 25(OH)D, fasting glucose, PTH, serum calcium, serum lipids, serum transaminases, and C-reactive protein were assessed. Indices of insulin sensitivity and resistance were determined from an oral glucose tolerance test. Subjects were classified as vitamin D deficient or sufficient, based on the traditional vitamin D deficiency definition [serum 25(OH)D <20 ng/ml] and also by a lower 25(OH)D cut-point of 15 ng/ml or less. RESULTS: A total of 51 AA adolescent females (body mass index, 43.3 +/- 9.9 kg/m(2); age, 14 +/- 2 yr) were studied. Serum 25(OH)D concentrations were 20 ng/ml or less in 78.4% and 15 ng/ml or less in 60.8% of subjects. There were no significant group differences in the metabolic outcomes when subjects were classified using the traditional vitamin D deficiency definition. The Matsuda index of insulin sensitivity was significantly lower (P = 0.02), and insulin area under the curve was significantly higher (P = 0.04) in subjects with 25(OH)D concentrations of 15 ng/ml or less vs. those with higher concentrations. CONCLUSIONS:Vitamin D deficiency is highly prevalent in obese, AA female adolescents and may promote insulin resistance. Our data suggest that a 25(OH)D concentration of 15 ng/ml or less may be the threshold by which vitamin D deficiency confers negative effects on insulin sensitivity.
Authors: Kumaravel Rajakumar; John D Fernstrom; Michael F Holick; Janine E Janosky; Susan L Greenspan Journal: Obesity (Silver Spring) Date: 2008-01 Impact factor: 5.002
Authors: Lynae J Hanks; Krista Casazza; Ambika P Ashraf; Sasanka Ramanadham; Jamy Ard; Molly S Bray; T Mark Beasley; Jose R Fernandez Journal: J Bone Miner Metab Date: 2013-04-02 Impact factor: 2.626
Authors: Elena Rodríguez-Rodríguez; Rosa M Ortega; Liliana G González-Rodríguez; Ana M López-Sobaler Journal: Eur J Nutr Date: 2010-11-20 Impact factor: 5.614
Authors: Ambika P Ashraf; Jessica A Alvarez; Barbara A Gower; Karen H Saenz; Kenneth L McCormick Journal: Obesity (Silver Spring) Date: 2011-05-05 Impact factor: 5.002