Association Between Vitamin D and Inflammation and Diabetes Risk in Morbidly Obese Pre-Menopausal Women

Study Overview
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Brief Summary
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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.

Official Title
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Vitamin D, Inflammation, and Relations to Insulin Resistance in Morbidly Obese Pre-Menopausal Women

Conditions
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Insulin Sensitivity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Premenopausal women between the age of 21 and 49 years old BMI >=35(kg/m2) Not pregnant English speaking Approved for a bariatric surgery Exclusion Criteria: Subjects with: Diabetes Cancer Kidney disease Liver disease Gallbladder disease Rheumatoid arthritis HIV/AIDS Crohn's disease or inflammatory bowel disease Subjects taking anti-inflammatory medications

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 49 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No intervention<br>There is no intervention to subjects in this study. All subjects are morbidly women seeking bariatric surgeries. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oral Glucose Insulin Sensitivity (OGIS) | 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. | 2 hour, 1-5 weeks before bariatric surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Adipose tissue mRNA Expression of Vitamin D Receptors and Inflammation Markers |  | 10-20 minutes, during bariatric surgery | 
| Inflammatory markers in plasma | Fasting blood drawn on Oral Glucose Tolerance Test day, which is 1-5 weeks before bariatric surgeries | 3-15 minutes, 1-5 weeks before bariatric surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Inflammation, Vitamin D deficiency, Obesity