Pediatric Obesity Observational Prospective Trial
Condition: Pediatric Obesity
MeSH terms: Obesity; Pediatric Obesity
Study type: Observational

Summary: 
      Using an observational case-control cohort design, the investigator aims to define the
      mechanisms underlying microbiome regulation of metabolism in adolescence before and after
      medically indicated therapies for obesity. The investigator's overarching hypothesis is that
      gut bacteria control host weight, insulin sensitivity, and response to weight-loss treatments
      by modifying host metabolism.
    

Detailed description: 
      Intervention Cohorts: A prospective, longitudinal observational case control study will be
      performed. All subjects will receive Healthy Lifestyle Program (HLP) standard of care, which
      includes intensive lifestyle modification and free participation in Bull City Fit. Four
      groups of participants receiving obesity treatment will be enrolled: (1) HLP-only, (2) HLP +
      Low carbohydrate diet, (3) HLP + weight loss medication(s) and (4) HLP + Bariatric surgery.
      Consistent with the observational design of this study, study participants will be assigned
      to each group as per usual HLP clinical care, based on established standards and guidelines,
      expert medical provider recommendations, and family preference.

      Comparison Cohort: two comparison groups be enrolled:(1c) healthy siblings of enrolled
      intervention subjects and (2c) age/sex matched controls recruited from the Duke Children's
      Primary Care Clinic.

      Up to 350 participants will be enrolled, with the goal of 295 evaluable participant data. The
      study period is six months for all groups with the exception of the bariatric surgery group
      which will last from baseline until after surgery, up to 12 months. The comparison groups
      will have one visit at baseline only.

      Stool Sample Collection: Participants in both intervention and comparison groups will provide
      a fecal sample at enrollment or within 3 days of enrollment. Participants in intervention
      groups (Groups 1-4) will provide additional fecal samples at 1.5, 3, 4.5, and 6 months. Given
      that the ability to collect fecal samples is unpredictable, the investigator will develop a
      standard operating procedure along the following guidelines:

        1. At the first visit, if the subject cannot provide a sample at the time of enrollment,
           the investigator will give the participant/parent a cooler/ice pack and sample
           collection kit. The investigator will ask the subject to provide the "baseline" sample
           within 3 days of the first visit. The sample will be refrigerated for up to 24 hours
           prior to pick up by the clinical research staff or delivery by the parent/guardian, with
           compensation for miles. With pick up or delivery a new cooler and freezer pack as well
           as sample collection kit will be provided for the following sample collection.

        2. Within a 2-week window, centered on collection points 1.5 and 4.5 months, the subjects
           will provide additional samples. They may either have the samples picked up within 24
           hours of collection (with refrigeration from collection to pick up) or get reimbursed
           for mileage.

        3. For the 3-month and 6-month collections, which occur in conjunction with a regularly
           scheduled Healthy Lifestyles visit, the patients will collect a sample within 24 hours
           prior to the visit and bring with them to clinic. At the 3-month visit they will be sent
           home with new collection kits, freezer packs, and coolers.

        4. If a patient cannot provide a sample within 24 hours of a clinic visit or a sample is
           missed, we will still collect a sample as soon as the patient is able to provide it and
           arrange for pickup or delivery as outlined below, noting the sample as "out of window."

      Plasma sample collection: Participants in intervention groups will provide a 20mL blood
      samples at baseline, 3 and 6 months at the time of a regular HLP visit. The standard HLP
      clinical protocol is to draw fasting labs at baseline and 6 months, so no additional blood
      draws beyond what is required for clinical care will be required at those visits. However,
      HLP patients do not typically have a blood draw at 3 months, so participants will be asked
      for a blood sample at 3 months they would not otherwise require. Participants in comparison
      groups (Groups 1c, 2c) will be asked for a blood sample at enrollment only; they would not
      otherwise require this sample.

      Analysis of samples: Fecal samples will be analyzed for the composition of the microbiota
      using DNA sequencing methods. Specific bacteria associated with obesity will be isolated from
      fecal samples and studied in the laboratory for their metabolism. A subset of fecal samples
      will be transferred into the intestinal tracts of germ free mice to study the effects on
      their metabolism. Participant plasma will be analyzed for panels of metabolites that are
      associated with diabetes mellitus and obesity. Blood mononuclear cell DNA will be used for
      focused genetic testing to identify genetic changes associated with obesity.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Duke Healthy Lifestyles (HL) Clinic Patients with BMI>95%

          1. c) Normal-weight siblings of patients presenting to the Duke Healthy Lifestyles Clinic

          2. c) Normal weight age/sex-matched controls presenting for well-child care to Duke
             Children's Primary Care clinic
      
Biospecimen description: 
      Fecal samples: Samples will be kept at 4ºC for < 18 hours prior to moving to the lab -80ºC
      freezer.

      Using the Human Microbiome Roadmap (REFS), Ribosomal DNA will be amplified using multiplexing
      primers per Caparoso et al method. Pooled amplicons will be sequenced. Sequences will be
      stored on the Center for Genomes in Microbial Systems (GeMS) without PHI.

      A 20 mL(milliliter) blood sample will be collected for isolation of mononuclear cells and
      plasma for genetic and metabolomics studies.

      Sampling will not exceed 2 ml/kg or 90 ml over the course of the study. Mononuclear cell DNA
      will be isolated from peripheral samples and applied to a focused polymorphism analysis for
      29 obesity risk alleles using Sequenom technology at the David H. Murdock Research Institute.