Brain Regulation of Appetite in Twins

Study Overview
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Brief Summary
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Scientists are examining the genetic and environmental influences on appetite and weight gain. The main purpose of this study is to look at how genetic and environmental factors may influence how the brain regulates appetite and food intake. Understanding how the brain regulates appetite and food intake may eventually lead to new ways to help people avoid obesity or lose weight.

Official Title
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Brain Regulation of Appetite in Twins

Conditions
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Obesity, Appetite

Intervention / Treatment
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* Device: Functional Magnetic Resonance Imaging
* Radiation: Dual Energy X-ray absorptiometry
* Other: Questionnaires
* Other: Mood and Appetite Ratings
* Other: Test Meals
* Other: Computer Tests
* Procedure: Intravenous Catheter (IV) placement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ability and willingness to come with their twin to the University of Washington (Seattle) Additional Criteria for Aim 1 random sample only: Member of randomly selected MZ pair or Additional criteria for Aim 2 random sample only: One member of MZ or same-sex DZ pair with BMI of at least 30 kg/m^2 Additional criteria for Aim 3 sample only: Member of randomly selected MZ pair, and not BMI discordant ≥ 5 kg/m^2 Exclusion Criteria: History of weight loss surgery or active participation in weight loss program Major medical problem (e.g., diabetes, cancer) Current use of weight loss medications or other medications known to alter appetite Pregnancy or menopause MRI contraindication (i.e., implanted metal, claustrophobia) Lifetime eating disorder Current smoking Current heavy alcohol use (≥2 drinks per day for females and ≥ 3 drinks per day for males) Self-reported weight >330 pounds at time of phone screening. MRI cannot accommodate all shapes or weights. Inability to have MRI does not exclude subject from participating in other study procedures. BMI < 18.5 or > 45 kg/m^2 Allergies to study foods or inability to taste Twins were raised apart Co-twin not eligible or not willing to participate

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| 27 Monozygotic Pairs<br> | Device: Functional Magnetic Resonance Imaging<br>* Measure brain activity.<br>* Other names: fMRI;Radiation: Dual Energy X-ray absorptiometry<br>* Body composition measurements.<br>* Other names: DXA;Other: Questionnaires<br>* Questionnaires related to: health, weight, sleep, mood, dietary habits, attitudes towards eating, how you describe yourself.<br>Other: Mood and Appetite Ratings<br>* Answer questions about how you are feeling at the moment.<br>Other: Test Meals<br>* Breakfast, a snack, and lunch provided during study visit.<br>Other: Computer Tests<br>* Perform a series of computer tests to determine reaction time.<br>Procedure: Intravenous Catheter (IV) placement<br>* Blood samples collected throughout regular intervals during the study visit day to measure levels of hormones involved in regulating appetite and body weight. We will also determine if twins are fraternal or identical and will examine DNA to see if participants carry two genes that affect appetite or body weight, the FTO gene and the MC4R gene.<br>|
| 27 Dizygotic Pairs<br> | Device: Functional Magnetic Resonance Imaging<br>* Measure brain activity.<br>* Other names: fMRI;Radiation: Dual Energy X-ray absorptiometry<br>* Body composition measurements.<br>* Other names: DXA;Other: Questionnaires<br>* Questionnaires related to: health, weight, sleep, mood, dietary habits, attitudes towards eating, how you describe yourself.<br>Other: Mood and Appetite Ratings<br>* Answer questions about how you are feeling at the moment.<br>Other: Test Meals<br>* Breakfast, a snack, and lunch provided during study visit.<br>Other: Computer Tests<br>* Perform a series of computer tests to determine reaction time.<br>Procedure: Intravenous Catheter (IV) placement<br>* Blood samples collected throughout regular intervals during the study visit day to measure levels of hormones involved in regulating appetite and body weight. We will also determine if twins are fraternal or identical and will examine DNA to see if participants carry two genes that affect appetite or body weight, the FTO gene and the MC4R gene.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Meal-induced nutrient and hormonal changes in plasma (insulin, GLP-1, ghrelin, glucose) |  | Baseline | 
| Brain activation during fMRI in satiety-related regions |  | Baseline | 
| Body composition: fasting leptin and dual energy X-ray absorptiometry (DXA) |  | Baseline | 
| DNA evaluation of FTO genotypes |  | Baseline | 
| Objective satiety: caloric and macronutrient intake |  | Baseline | 
| Subjective satiety: visual analog scale (VAS) scores and appeal ratings |  | Baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Twins, Obesity, Appetite