Blood Pressure in Blacks and Calcium (BBC) and Vitamin D Study
试验速览
- 阶段
- 2 期
- 状态
- 已完成
- 发起方
- 入组人数
- 5
- 试验地点
- 1
- 主要终点
- Change in Mean Blood Pressure From Baseline to 12 Weeks
研究概览
简要总结
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.
详细描述
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:
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 25 Years 至 45 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Age 25-45 years
- •Self-reported race/ethnicity African American
- •BMI ≥ 18 kg/m2
- •Total 25(OH)D levels < 20 ng/ml (50 nmol/L)
- •No use of vitamin D supplements within past 30 days of the screening visit
- •Able to provide written informed consent
- •Willing to take a vitamin D supplement daily for 3 months
- •Willing to return for follow-up visits to measure blood pressure and provide a blood sample to measure vitamin D and serum calcium
- •No current use of blood pressure lowering medications
- •Systolic blood pressure ≥ 100 mmHg and diastolic blood pressure ≥ 60 mmHg
排除标准
- •Medical history of chronic disease that affect gastrointestinal absorption of vitamin D: Crohn's disease, cystic fibrosis, and celiac disease
- •Use of medications which may affect total 25(OH)D levels: antiepileptic drugs, steroids, bile acid sequestrants, lipase inhibitors, orlistat
- •Current use of vitamin D supplements or use in past month and unwillingness to discontinue for at least 1 month prior to study enrollment
- •History of kidney stones or hypercalciuria
- •Fasting serum calcium ≥ 10.2 mg/dl
- •Average systolic blood pressure ≥ 140 mmHg
- •Average diastolic blood pressure ≥ 90 mmHg
- •Presence of type 1 diabetes mellitus, active malignancy, active thyroid disease or sarcoidosis
- •Pregnant or planning a pregnancy
- •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
研究组 & 干预措施
Vitamin D
Participants will all receive supplementation with cholecalciferol 5000 IU and calcium citrate 1000 mg daily for 3 months
干预措施: Cholecalciferol (Drug)
结局指标
主要结局
Change in Mean Blood Pressure From Baseline to 12 Weeks
时间窗: Difference in BP from baseline and 12 weeks after initiation of intervention
Seated blood pressure is measured at baseline and at 6 and 12 week follow-up visits in the clinic using an appropriate sized cuff after a rest period using an automated device (Omron). Blood pressure will be measured three times in one minute intervals at each time point and the average of these three recordings will be recorded as the mean blood pressure at each time point. Arm circumference will be measured to ensure the correct cuff size is used for all blood pressure measurements including home monitoring of blood pressure. Due to small number of participants, the change in mean blood pressure was analyzed as difference in mean blood pressure (2 x average diastolic blood pressure + average systolic blood pressure)/3 between baseline and at 12 weeks.
次要结局
- Change in Free 25-hydroxyvitamin D Levels From Baseline to 12 Weeks(Baseline and at 12 weeks after initiation of intervention)
- Change in 1,25-dihydroxyvitamin D From Baseline to 12 Weeks(Change in 1,25 dihydroxyvitamin D levels from baseline and at 12 weeks after initiation of intervention)
- Change in 24-hour Urine Calcium Excretion From Baseline to 12 Weeks(Change in 24 hour urine calcium excretion from baseline and at 12 weeks after initiation of intervention)
- Change in Total 25-hydroxyvitamin D From Baseline to 12 Weeks(Change in total 25-hydroxyvitamin D level from baseline to 12 weeks after initiation of intervention)
- Change in Intact Parathyroid Hormone Levels From Baseline to 12 Weeks(Change in PTH levels from baseline and at 12 weeks after initiation of intervention)
研究者
Holly J. Mattix-Kramer
Associate Professor
Loyola University