Calcium Absorption Efficiency As An Indicator For Vitamin D Sufficiency
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 76
- 试验地点
- 1
- 主要终点
- To determine the level of 25OHD that maximizes calcium absorption efficiency.
研究概览
简要总结
The purpose of this study is to determine the capability to absorb calcium as a measure of the sufficient levels of Vitamin D. Calcium absorption will be measured at baseline and after vitamin D3, by dual calcium isotope technique using stable isotopes in post menopausal women between the ages 50 and 70yrs. Subjects will have a screening visit, first and final visits. Subjects will be randomly assigned to a placebo or daily doses of vitamin D3. The specific aim of this study is to determine the level of vitamin D that will maximize the absorption of calcium and establish the relationship between the administered calcium dose and the actual absorbed calcium dose versus administered dose of Vitamin D and the serum levels of Vitamin D.
详细描述
The specific aims of this project are:
- To determine the level of 25OHD that maximizes calcium absorption efficiency.
- To describe the dose response curve of calcium absorption to vitamin D intake and serum 25OHD.
This will be a randomized, double-blind, placebo-controlled trial of healthy postmenopausal females to determine the individual and combined effects of calcium and vitamin D supplementation.70 female participants, ages 50 to 70 years of age who are menopausal for over 1 year will be recruited into the study . The patients participation in this study will last about 10 weeks. Approximately 70 subjects from Winthrop University Hospital and the surrounding area will participate in this study. There is a total of 3 visits. Patients will be fasting for all visits. The first visit is a screening visit to determine if the patients qualify.
At visit 2, the patients will be given a light breakfast and asked to drink an 8 ounce glass of milk or calcium fortified orange juice containing a calcium isotope. After breakfast, the doctor or nurse will start an intravenous infusion and inject the patient with an IV solution containing a calcium isotope. This is a stable calcium isotope that is not radioactive and has no known toxicity. The patients will also be asked to collect a 24 hour urine and return it to us the next day.
The volunteers will be divided into four groups:
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Single Group
- 主要目的
- Diagnostic
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 50 Years 至 70 Years（Adult, Older Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Post menopausal women between the ages 50-70 yrs.
排除标准
- •Any chronic medical illness including diabetes mellitus, history of myocardial infarction, or heart failure, malignancy, uncontrolled hypertension, history of anemia, leukemia, or other hematologic abnormalities, lupus, rheumatoid arthritis, or other rheumatologic disease, or kidney disease of any kind as determined by history and physical examination.
- •Subjects with a BMI >35kg/m2
- •Use of medication that influences vitamin D and bone metabolism (i.e. anticonvulsant medications, glucocorticoids, HAART [AIDS treatment], antirejection medications, high dose diuretics etc).
- •Significant deviation from normal either in history, physical examination, or laboratory tests as evaluated by the primary investigator.
- •Patients with a history of hypercalciuria ( Urine calcium:creatinine ratio > 0.37 , hypercalcemia ( serum calcium >10.21, nephrolithiasis, and active sarcoidosis will also be excluded.
- •Unexplained weight loss >15% during the previous year or history of anorexia nervosa
- •Participation in another investigational trial in the past 30 days prior to the screening evaluation.
- •Patients reporting alcohol intake greater than 2 drinks daily.
- •Subjects with baseline 25-OHD level greater than 70 nmol /L will be excluded.
- •Smokers greater than one pack per day will be excluded
- •Dietary calcium intake greater than 2000 mg will be excluded
- •Participants who have history of allergy to milk, gluten or orange juice will be excluded
- •Participants willing not to forego multivitamins and vitamin D supplements during the study -
研究组 & 干预措施
Post Menopausal
post menopausal women between the ages 50-70 yrs.
干预措施: Dual isotope technique (Other)
结局指标
主要结局
To determine the level of 25OHD that maximizes calcium absorption efficiency.
时间窗: 3 months
次要结局
- To describe the dose response curve of calcium absorption to vitamin D intake and serum 25OHD(3 months)
研究者
John F. Aloia, MD
Principal Investigator
Winthrop University Hospital