Clinical trial NCT00994396: Vitamin D to Improve Glucose Metabolism and Reduce Inflammation in Obese Adolescents
Official title: Use of Vitamin D to Improve Glucose Metabolism and Reduce Inflammation in Obese Adolescents on a Standard Weight Loss Program
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Obesity
Glucose Intolerance
Inflammation
Lead sponsor: University of Missouri-Columbia
Sponsor class: OTHER
First posted: 2009-10-14
Enrollment: 44
Sex: ALL
Minimum age (years): 9
Maximum age (years): 19
Standard ages: CHILD
ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: The investigators' project will study the effects of optimizing the vit D status of obese adolescents on markers of glucose metabolism and inflammation.

Detailed description: The alarming rise in pediatric obesity over the past few decades has been associated with an increase in the occurrence of impaired glucose tolerance and inflammation in children and adolescents. These conditions are part of the "metabolic syndrome", and children with risk factors such as these are much more likely to develop cardiovascular disease or diabetes as adults compared with their lean peers. Within the last few years there has been a growing body of evidence that optimizing vitamin D (vit D) status may alleviate these obesity-associated complications. Further, there is also research that shows that the better the vit D status of overweight individuals, the more favorably they respond to dieting by losing more body fat. The prevalence of vit D deficiency/insufficiency in the North American population has been classified as an "epidemic" by experts in the field and obese teens are considered at an even greater risk for deficiency because they tend to store vit D in their fat stores which is not readily mobilized for use by the body. The investigators' project will study the effects of optimizing the vit D status of obese adolescents on markers of glucose metabolism and inflammation. Obese teens attending an established adolescent weight loss clinic will be supplemented with high-dose vit D for 6 months (mos) which will be administered concurrently with their standard medical care and treatment. At baseline, 3 mos and 6 mos the investigators will measure vit D status, serum markers of insulin sensitivity and glucose metabolism; serum markers of inflammation; and body weight/height and waist circumference. At baseline and 6 mos only the investigators also measure body composition (percent body fat by dual-energy x-ray absorptiometry) and confounding lifestyle factors known to affect vit D, glucose metabolism or inflammation (e.g., nutrient intake, physical activity, sun exposure, pubertal stage). Results gleaned from this study will help to advance the prevention and treatment of obesity-related complications and have the potential to lead to significant reductions in healthcare costs and co-morbidities.

Eligibility criteria: Inclusion Criteria:

* Obese adolescent (BMI \> 85th percentile for age)
* 9-19 years of age
* attending the ADOBE clinic at the University of Missouri

Exclusion Criteria:

* use of vit D supplements other than standard multi-vitamin preparation
* (i.e., should not be receiving vit D \> 1000 IU/d) use of medications that interfere with vit D metabolism (e.g., anti-convulsive)
* history of hepatic or renal disorders;
* undergoing ultraviolet radiation as medical therapy;
* pregnancy;
* cigarette smoking;
* current use of commercial tanning bed;

Primary outcomes:
measure: serum 25-hydroxy vitamin D concentrations
timeFrame: baseline, 3, 6 months
measure: serum concentrations of inflammatory markers (Interleukin-6, TNF-alpha, c reactive protein)
timeFrame: baseline and 6 mos
measure: Hemoglobin A1C, serum glucose and insulin concentrations
timeFrame: baseline, 3 and 6 months
Secondary outcomes:
measure: Body composition as measured by DXA
timeFrame: baseline and 6 mos
measure: Body mass index
timeFrame: baseline, 3 and 6 months
Other outcomes:
Locations:
city: Columbia
country: United States
facility: University of Missouri
state: Missouri
Study officials:
affiliation: University of Missouri-Columbia
name: Catherine A Peterson, Ph.D.
role: PRINCIPAL_INVESTIGATOR
References:
citation: Belenchia AM, Tosh AK, Hillman LS, Peterson CA. Correcting vitamin D insufficiency improves insulin sensitivity in obese adolescents: a randomized controlled trial. Am J Clin Nutr. 2013 Apr;97(4):774-81. doi: 10.3945/ajcn.112.050013. Epub 2013 Feb 13.