Document Type



Doctor of Philosophy (PhD)


Dietetics and Nutrition

First Advisor's Name

Fatma Huffman

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Adriana Campa

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Zisca Dixon

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Tan Li

Fourth Advisor's Committee Title

Committee member


diabetes, vitamin D, glucose, lipids, Hispanics

Date of Defense



The aim of the present study was to determine the effect of vitamin D supplementation (4000 IU or 6000 IU of cholecalciferol daily for 6 months) on fasting plasma glucose, fasting insulin, glycated hemoglobin, and lipid profile in a sample of African-Americans and Hispanics with T2D and vitamin D insufficiency. Seventy five participants were recruited by community outreach. Plasma glucose concentration was measured by hexokinase enzymatic method. Glycated hemoglobin was measured by the DCA2000+ system. Insulin in fasting blood was determined by radioimmunoassay. Plasma total cholesterol, triglycerides, low-density lipoprotein, and high-density lipoprotein cholesterol were assayed by enzymatic methods. Serum vitamin D concentrations were measured with an enzyme-immunoassay kit. Mixed model was used to compare treatment effects and Bonferroni multiple comparison tests was used to detect significant changes from baseline, 3 months, and 6 months on the outcome variables. Significant improvements in serum 25(OH)D levels were seen from baseline to 3 month and 6 months respectively in both treatments (from 22.25 ± 7.19 to 37.34 ± 12.31 and 37.99 ± 13.22, PPP=0.040) was observed. Similarly, a significant change in serum triglycerides was observed at 6 months in the 6000 IU group (from 201.44 ± 91.35 to 172.92 ± 76.87 mg/dl, P=0.037). However, when the model was adjusted for confounders, significance was lost. Vitamin D supplementation did not improve glucose homeostasis in this sample. The positive effect of vitamin D supplementation on lipid profile may be mediated by other cofactors related to vitamin D metabolism.





Rights Statement

Rights Statement

In Copyright. URI:
This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).