Association Between Vitamin D and Inflammation and Diabetes Risk in Morbidly Obese Pre-Menopausal Women
Obesity is associated with low-grade inflammation, insulin resistance and low vitamin D status. Vitamin D has traditionally been known to involve in calcium homeostasis and prevent rickets; however, recently it has been recognized to inversely associate with many non-skeletal diseases and conditions including obesity and type 2 diabetes (T2DM). In vitro studies have demonstrated that vitamin D possesses anti-inflammatory properties. It remains unknown if the effect of vitamin D on insulin sensitivity is mediated by suppressing inflammation in human adipose tissues. The main objective of this study was to assess the association between vitamin D and insulin sensitivity and inflammation in morbidly obese pre-menopausal women. Obese women (n=76) were recruited from the University of Illinois at Chicago (UIC) Nutrition and Wellness Center and the UIC medical center bariatric surgery clinics. Insulin sensitivity/resistance was assessed by (1) Oral glucose insulin sensitivity (OGIS) index, derived from dynamic oral glucose tolerance test (OGTT), and (2) Homeostasis model of insulin resistance (HOMA-IR), calculated from fasting steady-state glucose and insulin. Also, to better understand the potential mechanism and the role circulating vitamin D (25OHD) plays in adipose tissue inflammation, we assessed messenger ribonucleic acid (mRNA) expression of vitamin D receptor (VDR) and various inflammatory genes in visceral (VAT) and subcutaneous adipose tissues (SAT) of obese women that underwent a restrictive bariatric procedure. We hypothesized that subjects with higher serum vitamin D levels would be less inflamed and more insulin sensitive and have increased expression of VDR and pro-inflammatory markers compared to those with lower serum vitamin D levels.
|Study Type:||Observational [Patient Registry]|
|Study Design:||Observational Model: Case-Only
Time Perspective: Cross-Sectional
|Target Follow-Up Duration:||2 Months|
|Official Title:||Vitamin D, Inflammation, and Relations to Insulin Resistance in Morbidly Obese Pre-Menopausal Women|
- Oral Glucose Insulin Sensitivity (OGIS) [ Time Frame: 2 hour, 1-5 weeks before bariatric surgery ] [ Designated as safety issue: No ]Insulin sensitivity is assessed based with a 2-hour, 75gm Oral Glucose Tolerance Test. Blood samples are collected at 0, 90, and 120 min for the measurement of glucose and insulin.
- Adipose tissue mRNA Expression of Vitamin D Receptors and Inflammation Markers [ Time Frame: 10-20 minutes, during bariatric surgery ] [ Designated as safety issue: No ]
- Inflammatory markers in plasma [ Time Frame: 3-15 minutes, 1-5 weeks before bariatric surgery ] [ Designated as safety issue: No ]Fasting blood drawn on Oral Glucose Tolerance Test day, which is 1-5 weeks before bariatric surgeries
Biospecimen Retention: Samples With DNA
Plasma Adipose tissues
|Study Start Date:||May 2011|
|Study Completion Date:||February 2013|
|Primary Completion Date:||February 2013 (Final data collection date for primary outcome measure)|
There is no intervention to subjects in this study. All subjects are morbidly women seeking bariatric surgeries.
Please refer to this study by its ClinicalTrials.gov identifier: NCT02169050
|United States, Illinois|
|University of Illinois at Chicago|
|Chicago, Illinois, United States, 60612|
|Principal Investigator:||Carol Braunschweig, PhD||University of Illinois at Chicago|