Blood Pressure in Blacks and Calcium (BBC) and Vitamin D Study
Condition: Hypertension; Vitamin D Deficiency
MeSH terms: Vitamin D Deficiency
Intervention: Cholecalciferol
Intervention description: 5000 IU cholecalciferol with 1000 mg calcium citrate daily
Intervention MeSH terms: Vitamin D; Cholecalciferol
Phase: Phase 2
Study type: Interventional
Primary purpose: Prevention
Intervention model: Single Group Assignment
Intervention model description: This pilot study is a one arm study which will assess the safety and feasibility of supplementing 15 young adults with African ancestry and low vitamin D levels with 5,000 IU of Cholecalciferol (vitamin D3) combined with 1000 mg of elemental calcium daily for 3 months
Masking: None (Open Label)
Enrollment: 5.0
Sex: All
Minimum age: 25 Years
Maximum age: 45 Years
Healthy volunteers: Accepts Healthy Volunteers

Summary:

      Adequate levels of vitamin D are essential for bone health at all ages but low levels of
      vitamin D may also negatively impact other aspects of health such as blood pressure. The
      investigators have previously shown that adults with African ancestry living near the equator
      have much higher levels of vitamin D and higher levels of blood pressure compared to adults
      with African ancestry living in the Chicago area. Multiple clinical trials have examined
      vitamin D supplementation for reducing blood pressure levels but very few studies have
      focused on adults with African ancestry and low vitamin D levels. In addition, most previous
      clinical trials have not addressed calcium intake. While vitamin D may modulate blood
      pressure via its actions on activation of the renin angiotensin aldosterone system, it is
      also possible that vitamin D mediates blood pressure via its effects on gastrointestinal
      calcium absorption. This pilot study is a one arm study, which will assess the safety and
      feasibility of supplementing 15 young adults with African ancestry and low vitamin D levels
      with 5,000 IU of Cholecalciferol (vitamin D3) combined with 1000 mg of elemental calcium
      daily for 3 months. Participants will be recruited from the Maywood Illinois and surrounding
      areas with flyers and brochures. The investigators will also contact previous participants of
      the Modeling the Epidemiologic Study/Vitamin D Ancillary Study by phone and letters. At
      baseline, all participants will have blood pressure measured and will provide a fasting serum
      specimen and a 24-hour urine collection. Calcium, parathyroid hormone level vitamin D will be
      measured in serum specimens and 24-hour urine calcium excretion will be measured. Repeat
      visits will be completed at 6 and 12 weeks of follow-up to again measure resting blood
      pressure and serum calcium and vitamin D levels. The overall goal is to collect pilot data to
      help design a larger trial of vitamin D and calcium supplementation for lowering blood
      pressure in young adults with African ancestry.
    

Eligibility criteria:

        Inclusion Criteria:

          1. Age 25-45 years

          2. Self-reported race/ethnicity African American

          3. BMI ≥ 18 kg/m2

          4. Total 25(OH)D levels < 20 ng/ml (50 nmol/L)

          5. No use of vitamin D supplements within past 30 days of the screening visit

          6. Able to provide written informed consent

          7. Willing to take a vitamin D supplement daily for 3 months

          8. Willing to return for follow-up visits to measure blood pressure and provide a blood
             sample to measure vitamin D and serum calcium

          9. No current use of blood pressure lowering medications

         10. Systolic blood pressure ≥ 100 mmHg and diastolic blood pressure ≥ 60 mmHg

        Exclusion Criteria:

          1. Medical history of chronic disease that affect gastrointestinal absorption of vitamin
             D: Crohn's disease, cystic fibrosis, and celiac disease

          2. Use of medications which may affect total 25(OH)D levels: antiepileptic drugs,
             steroids, bile acid sequestrants, lipase inhibitors, orlistat

          3. Current use of vitamin D supplements or use in past month and unwillingness to
             discontinue for at least 1 month prior to study enrollment

          4. History of kidney stones or hypercalciuria

          5. Fasting serum calcium ≥ 10.2 mg/dl

          6. Average systolic blood pressure ≥ 140 mmHg

          7. Average diastolic blood pressure ≥ 90 mmHg

          8. Presence of type 1 diabetes mellitus, active malignancy, active thyroid disease or
             sarcoidosis

          9. Pregnant or planning a pregnancy

         10. Estimated glomerular filtration rate (based on serum creatinine level) is < 60
             ml/min/1.73 m2 based on the Modification of Diet in Renal Disease formula