Efficacy of Vitamin D Supplementation in Obese Children
Condition: Obesity, Pediatric; Obesity, Childhood; Obesity, Morbid; Vitamin D Deficiency
MeSH terms: Obesity; Vitamin D Deficiency; Obesity, Morbid; Pediatric Obesity
Study type: Interventional

Summary: 
      Vitamin D deficiency is common in the general population in the United States, but is more
      common in overweight and obese children. Additionally, vitamin D levels are inversely
      correlated with body mass index, hypertension, inflammatory markers and insulin resistance.
      There are currently no clear guidelines regarding vitamin D replacement in obese but
      otherwise healthy children. The Endocrine Society recommends that children with vitamin D
      deficiency should take 2000 IU once a day for at least 6 weeks; however, they state that
      obese children may need 2-3 times this dose in order to reach sufficient levels.

      The goals of this study are:

        1. To determine the prevalence of vitamin D sufficiency (>30 ng/mL), insufficiency (21-29
           ng/mL); deficiency (10-19 ng/mL) and severe vitamin D deficiency (<10 ng/dL) in an obese
           pediatric population (2-11 years) as measured by 25-hydroxyvitamin D.

        2. To determine if vitamin D level correlates with percentage body fat by bioelectrical
           impedance analysis and/or visceral fat by waist circumference in children ages 5 - 11
           years.

        3. To observe the effect of vitamin D replacement in obese children with vitamin D
           deficiency using two different replacement dosage levels recommended by the Endocrine
           Society over three months: 2000 IU once a day (general pediatric dose) vs 6000 IU once a
           day (suggested obesity dose) in children between the ages of 5 - 11 years.

        4. To measure vitamin D levels, bone markers, inflammatory markers and vitamin D binding
           protein before and after vitamin D supplementation in children between the ages of 5 -
           11 years. Analysis will be stratified by degree of obesity (Class I, Class II, Class
           III) and season.
    

Detailed description: 
      Study subjects will be obese children between the ages of 2 and 11 years who are being seen
      at the FIT (Families Improving Health Together) program. As part of their routine care, all
      patients seen at the FIT program will have weight measured to the nearest 0.1 kilogram by
      digital floor scale, stature by wall-mounted stadiometer and waist circumference measurements
      to the nearest 0.1 centimeter. BMI will be calculated as weight in kilograms, divided by
      height in meters squared (kg/m2). Waist circumference will be measured with a tape measure at
      the uppermost lateral border of the hip crest (ilium). Percentage body fat will be
      approximated by bioelectrical impedance analysis. All patients will have 25-hydroxyvitamin D
      measured, which will be sent to Esoterix Labs (Calabasas Hills, CA) and run by high-pressure
      liquid chromatography/tandem mass spectrometry (HPLC/MS-MS). Other baseline labs that will be
      drawn include glucose, insulin, hemoglobin A1c, lipid panel, hepatic function panel and basic
      metabolic panel. Blood from the initial visit will be banked for future research laboratory
      testing as part of the overall goal of the FIT program. The research labs that will be run
      include vitamin D binding protein, osteocalcin, c-telopeptide, P1NP, PTH, IL-6 and TNF-alpha.

      Vitamin D prevalence information and baseline labs and anthropometrics will be obtained from
      all patients who agree to participate in the study; however, bioelectrical impedance analysis
      will not be performed in patients under 5 years. Patients between the ages of 5 and 11 years
      who have a 25-hydroxyvitamin D below 21 ng/mL will be invited to participate in vitamin D
      supplementation portion of the study. These patients will be treated with vitamin D3
      supplementation of either 2000 IU once a day or 6000 IU once a day. Dose will be determined
      by a set dosing schedule. Each provider will be assigned a dosing schedule and dosing
      schedules that will change every 3 months over 2 years. The dosing schedule can be found in
      the study documents section. This study design is intended to minimize bias based on provider
      or season. Eligible patients who agree to participate in the study will purchase the
      prescribed dose of vitamin D3, which is an over the counter medication. Vitamin D3 is
      supplied over the counter as drops, liquid, chewable tablets, gummies, tablets or capsules
      and parents will select the form that is easiest for their child to take. They will supply us
      with a picture of the vitamin D3 label so that we can ensure they are taking the appropriate
      dose and form of vitamin D. They will take the prescribed dose every day for three months.
      Patients will get weekly reminder calls to ensure that they are taking the supplement as
      prescribed. At the end of three months they will return for their scheduled clinic
      appointment. Weight, height, waist circumference and percentage body fat will be measured and
      labs will be redrawn including 25-hydroxyvitamin D glucose, insulin, hemoglobin A1c, lipid
      panel, hepatic function panel and basic metabolic panel and the research labs described above
      will be drawn as well. At the end of 3 months if vitamin D is 21 ng/mL or above they will be
      advised to take vitamin D 1000 IU once a day; if their vitamin D continues to be below 21
      ng/mL they will be advised to continue their current dose of vitamin D.

      We expect to see on average about 8 new patients per week and we expect that at least 50% of
      them will have vitamin D level below 21 ng/mL and will be between the ages of 5 and 11 years.
      Over two years that amounts to 416 prospective study subjects. Dosages selected are based on
      the Endocrine Society Clinical Practice Guidelines (2011), which state that children with
      vitamin D deficiency should be treated with 2000 IU of vitamin D once a day; however obese
      children should be treated with 2-3 times that amount. In total we expect to enroll 192
      subjects over two years to the intervention portion of this trial (5 - 11 years) and we
      expect to enroll a total of 400 subjects to the observational portion (prevalence and
      associations with lab testing).

      Exclusion criteria include the following: Underlying disorder of bone metabolism, chronic
      renal failure, chronic steroid treatment (oral, inhaled or intranasal), current vitamin D
      supplementation other than that found in a daily multivitamin.
    

Intervention name(s): Vitamin D3
Intervention type(s): Dietary Supplement
Intervention description(s): Patients will be prescribed either 2000 IU or 6000 IU of vitamin D3 per day. They will go to a pharmacy and purchase a vitamin D3 supplement in their preferred form (eg gummy, liquid, chew, tablet, capsule)
Other intervention name(s): Cholecalciferol
Intervention MeSH terms: Vitamin D; Cholecalciferol
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Supportive Care
Keywords: Obesity; Pediatrics; Vitamin D deficiency