Obesity
Conditions
Keywords
Obesity, adolescent, ghrelin, growth hormone, cortisol
Brief summary
This study will examine hormonal differences in ghrelin and growth hormone in obese and normal weight adolescents and their relationship to body composition and insulin resistance. The study will also investigate the effect of the macronutrient composition of a meal on postprandial ghrelin levels and whether ghrelin responses will predict the degree of hunger and caloric intake at a subsequent meal.
Detailed description
Obesity is an epidemic that is striking people at younger ages than ever before. Obesity is associated with changes in the secretory patterns of several hormones including ghrelin, growth hormone (GH), and insulin, which have not been examined in the adolescent age group. Ghrelin, a primarily gastric hormone, increases appetite and is a GH secretagogue. This study will compare the alteration in secretion of ghrelin and GH in overweight and normal weight adolescent girls through frequent blood sampling and GH stimulation testing with growth hormone releasing hormone and arginine. The relationship between these hormones and insulin resistance, measured by 1H-nuclear magnetic resonance spectroscopy, and body composition, measured by dual energy x-ray absorptiometry and magnetic resonance imaging, will be investigated. This study will also determine the postprandial ghrelin response to test meals that vary by the type of predominant macronutrient, which may predict the degree of hunger and amount of intake at a subsequent meal. Understanding obesity-related changes in ghrelin and GH and their relationship to body composition, insulin resistance, and appetite will help in the development of strategies to reduce complications of obesity.
Interventions
None listed
Sponsors
Massachusetts General Hospital
Study design
Observational model
CASE_CONTROL
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
FEMALE
Age
12 Years to 18 Years
Healthy volunteers
Yes
Inclusion criteria
1. Girls 12-18 years of age 2. Obese subjects: BMI higher than the 95th percentile for age and sex 3. Normal-weight controls: BMI from the 15th to the 85th percentiles for age and sex
Exclusion criteria
1. History of disorders other than obesity that may affect growth hormone, ghrelin, cortisol, or insulin secretion such as eating disorder, diabetes mellitus, hypertension, thyroid disease, Cushing's syndrome, liver disease, renal failure, or an excess or deficiency of GH or cortisol 2. Medications that could affect glucose and lipid levels or the secretion of growth hormone, ghrelin, insulin, or cortisol such as rhGH, glucocorticoids, and birth control pills 3. Pregnancy 4. Smoking or substance abuse 5. Active dieting 6. Surgical procedures for obesity 7. Dietary restrictions such as bread, dairy, peanut, aspartame, or meat products used in the study 8. Metal implants, including intracranial surgical clips or pacemakers
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Peak Growth Hormone (GH) on the GH Stimulation Test | Baseline | Peak growth hormone (GH) on the GH stimulation test is a measure of the adequacy of GH secretion. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Visceral Adipose Tissue | Baseline | Visceral adipose tissue was measured using magnetic resonance imaging at the level of the fourth lumbar vertebra (L4) |
Countries
United States
Participant flow
Recruitment details
17 obese and 30 normal-weight adolescents (12-18 yr old) were screened for study eligibility.15 obese adolescents completed the study visit. These subjects were matched for race, ethnicity, and bone age to normal-weight adolescents from the pool of screened subjects.
Participants by arm
| Arm | Count |
|---|---|
| Normal-weight Girls Normal-weight girls were required to have a BMI between the 15th-85th percentiles | 15 |
| Obese Girls Obese girls were required to have a BMI above the 95th percentile | 15 |
| Total | 30 |
Baseline characteristics
| Characteristic | Normal-weight Girls | Obese Girls | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 15 Participants | 15 Participants | 30 Participants |
| Age, Categorical >=65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical Between 18 and 65 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Continuous | 15.9 years STANDARD_DEVIATION 1.7 | 14.0 years STANDARD_DEVIATION 1.9 | 14.9 years STANDARD_DEVIATION 3.3 |
| Sex: Female, Male Female | 15 Participants | 15 Participants | 30 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 0 / 15 | 0 / 15 |
| serious Total, serious adverse events | 0 / 15 | 0 / 15 |
Outcome results
Primary
Peak Growth Hormone (GH) on the GH Stimulation Test
Peak growth hormone (GH) on the GH stimulation test is a measure of the adequacy of GH secretion.
Time frame: Baseline
Population: This was a cross-sectional study to compare differences in growth hormone (GH) secretory status in relation to body composition in obese versus normal-weight girls. This was a pilot study and the analysis was performed using a Student t-test to compare means across groups
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Normal-weight Girls | Peak Growth Hormone (GH) on the GH Stimulation Test | 40.1 ng/ml | Standard Deviation 16.1 |
| Obese Girls | Peak Growth Hormone (GH) on the GH Stimulation Test | 25.2 ng/ml | Standard Deviation 21.8 |
Comparison: The null hypothesis was that there is no difference between the groups for peak growth hormone on the growth hormone stimulation test.p-value: <0.05t-test, 2 sided
Secondary
Visceral Adipose Tissue
Visceral adipose tissue was measured using magnetic resonance imaging at the level of the fourth lumbar vertebra (L4)
Time frame: Baseline
Population: The analysis was completed on the 30 participants as per protocol
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Normal-weight Girls | Visceral Adipose Tissue | 19 grams | Standard Deviation 7.5 |
| Obese Girls | Visceral Adipose Tissue | 42.7 grams | Standard Deviation 17 |
Comparison: The null hypothesis is that there is no difference between the groups for visceral adipose tissuep-value: <0.05t-test, 2 sided