Blood Pressure in Blacks and Calcium (BBC) and Vitamin D Study
Condition: Hypertension; Vitamin D Deficiency
MeSH terms: Vitamin D Deficiency
Study type: Interventional
Phase: Phase 2

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.
    

Detailed description: 
      This pilot study will recruit 15 black U.S. adults ages 25-45 years of age with 25(OH)D
      levels < 20 ng/ml and no use of anti-hypertensive medications and a resting seated systolic
      blood pressure ≥ 120 mmHg and will measure baseline levels of total 25(OH)D, 25(OH)D2,
      25(OH)D3, free vitamin 25(OH)D, active vitamin D [1,25(OH)D], parathyroid hormone level,
      serum calcium, and 24-hour calcium excretion.

      Participants will then take the supplements vitamin D3 5000 IU and elemental calcium 1000 mg
      daily for three months. Investigators will measure changes in blood pressure, total 25(OH)D,
      25(OH)D2 and 25(OH)D3, 1,25(OH)D and free 25(OH)D, parathyroid hormone levels, serum calcium
      and 24-hour urine calcium excretion over the three month period.

      The overall goal is to collect pilot data to determine the feasibility of a larger trial to
      determine whether vitamin D combined with calcium lowers blood pressure in young black adults
      with low 25(OH)D levels.

      This will be a single arm non-blinded feasibility study of 15 participants. The study
      population will consist of 15 adults ages 25-45 years with self-reported African American
      race/ethnicity. All participants will provide written informed consent.

      Intervention:

      This study has only one arm and all participants will receive Cholecalciferol (vitamin D3)
      5,000 IU daily for 3 months and 1000 mg of calcium citrate daily for 3 months. There will be
      no placebo and no blinding of the agent. Participants will receive a 3 month supply of drugs
      which will be administered by the Loyola pharmacy. Serum vitamin D and calcium levels will be
      measured at study initiation and at 6 and 12 weeks (study end). Participants will stop taking
      stop both vitamin D and calcium administration with serum calcium levels are greater than or
      equal to 10.6 meq/L and/or a 25(OH)D levels are greater than or equal to 80 ng/dl at the 6
      week visit.

      Safety Monitoring:

      The investigators will query any hospitalizations or emergency room visits over the past
      month and reasons for those visits at the baseline, 6 and 12 week follow-up visits. Serum
      calcium and vitamin D levels will be measured at 6 and 12 weeks and anyone with serum calcium
      levels ≥ 10.6 meq/L and/or a 25(OH)D level ≥ 80 ng/ml will stop treatment. All adverse events
      will be reported to the Loyola University Chicago Health Sciences Institutional Review Board.
      A data safety and monitoring board will review all data collected after completion of the 6
      week visit to ensure safety of the study.

      Stopping plans:

      Any participant who develops a serum calcium levels ≥ 10.6 meq/L and/or a 25(OH)D level ≥ 80
      ng/ml will stop treatment but they will continue to be monitored in the study through week 12
      when serum calcium and 25(OH)D levels will be measured at the end of the study. The study
      will continue until participants have been followed for 12 weeks.

      Analysis Plan:

      This feasibility study will examine multiple aspects of the pilot data including the total
      number of persons enrolled vs. number of total persons identified as eligible. Pill counts
      will be done at the 6 and 12 week visit to assess compliance with vitamin D and calcium
      supplementation. The percentage of participants taking 80% or more of the vitamin D3
      supplement and the calcium supplement will be determined. The number of participants
      reporting symptoms and all adverse events will be quantified. Repeated measures analysis of
      variance models will be used to assess change in the outcome measures including systolic and
      diastolic blood pressure, vitamin D measures, parathyroid hormone levels and 24-hour urine
      calcium excretion values.
    

Intervention name(s): Cholecalciferol
Intervention type(s): Drug
Intervention description(s): 5000 IU cholecalciferol with 1000 mg calcium citrate daily
Other intervention name(s): Vitamin D3
Intervention MeSH terms: Vitamin D; Cholecalciferol
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)
Primary purpose: Prevention