title: Vitamin D Supplementation Does Not Impact Insulin Resistance in Black and White Children.
abstract: Vitamin D supplementation trials with diabetes-related outcomes have been conducted almost exclusively in adults and provide equivocal findings.
  
  
  
  The objective of this study was to determine the dose-response of vitamin D supplementation on fasting glucose, insulin, and a surrogate measure of insulin resistance in white and black children aged 9–13 years, who participated in the Georgia, Purdue, and Indiana University (or GAPI) trial: a 12-week multisite, randomized, triple-masked, dose-response, placebo-controlled vitamin D trial.
  
  
  
  Black and white children in the early stages of puberty (N = 323, 50% male, 51% black) were equally randomized to receive vitamin D3 (0, 400, 1000, 2000, or 4000 IU/day) for 12 weeks. Fasting serum 25-hydroxyvitamin D (25(OH)D), glucose and insulin were assessed at baseline and weeks 6 and 12. Homeostasis model assessment of insulin resistance was used as a surrogate measure of insulin resistance. Statistical analyses were conducted as intent-to-treat using a mixed effects model.
  
  
  
  Baseline serum 25(OH)D was inversely associated with insulin (r = −0.140, P = 0.017) and homeostasis model assessment of insulin resistance (r = −0.146, P = 0.012) after adjusting for race, sex, age, pubertal maturation, fat mass, and body mass index. Glucose, insulin, and insulin resistance increased (F > 5.79, P < .003) over the 12 weeks, despite vitamin D dose-dependent increases in serum 25(OH)D.
  
  
  
  Despite significant baseline inverse relationships between serum 25(OH)D and measures of insulin resistance, vitamin D supplementation had no impact on fasting glucose, insulin, or a surrogate measure of insulin resistance over 12 weeks in apparently healthy children.
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Ashley J
authors.initials: AJ
authors.lastname: Ferira
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Emma M
authors.initials: EM
authors.lastname: Laing
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Dorothy B
authors.initials: DB
authors.lastname: Hausman
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Hall
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: George P
authors.initials: GP
authors.lastname: McCabe
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Berdine R
authors.initials: BR
authors.lastname: Martin
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Hill Gallant
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Warden
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Connie M
authors.initials: CM
authors.lastname: Weaver
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Munro
authors.initials: M
authors.lastname: Peacock
authors.affiliation: Departments of Foods and Nutrition (A.J.F., E.M.L., D.B.Hau., and R.D.L.) and Statistics (D.B.Hal.), The University of Georgia, Athens, Georgia 30602; Departments of Nutrition Science (C.M.W., B.R.M., K.M.H.G.) and Statistics (G.P.M.), Purdue University, West Lafayette, Indiana 47907; Department of Medicine (M.P.), Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Physical Therapy (S.J.W.), Indiana University School of Health and Rehabilitation Sciences, Indianapolis, Indiana 46202.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Lewis
mesh_terms: D000293:Adolescent; D044383:Black People; D001786:Blood Glucose; D001823:Body Composition / Q000502:physiology; D002648:Child; D002762:Cholecalciferol / Q000008:administration & dosage*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005215:Fasting / Q000097:blood; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D044465:White People
chemical_list: D001786:Blood Glucose; D007328:Insulin; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D