Vitamin D Dynamics in Pregnant Women and Non-Pregnant Women of Reproductive Age
试验速览
- 阶段
- 不适用
- 状态
- 招募中
- 入组人数
- 160
- 试验地点
- 1
- 主要终点
- Impact of pregnancy on serum vitamin D absorption
研究概览
简要总结
The goal of this project is to utilize stable isotopically labeled vitamin D3 and state of the art mass spectrometric methodology to assess vitamin D dynamics during pregnancy in relation to relation to obesity and vitamin D binding protein genotype. At the conclusion of this study, the investigators will have obtained novel information on the absorption and utilization of vitamin D in women and the degree to which vitamin D utilization during pregnancy is impacted by genetic ancestry, vitamin D binding protein concentration and genotype and by excess adiposity. The long-term goal is to better understand the unique metabolism of vitamin D during pregnancy.
详细描述
Nearly 30% of US women are either vitamin D insufficient or deficient. Vitamin D inadequacy during gestation is increasingly linked to adverse birth outcomes including preterm birth, the risk of cesarean section and placental and pregnancy-associated infections. At this time the Institute of Medicine (IOM) has not advocated any increase in vitamin D intake across gestation but this remains controversial in large part due to insufficient information on the basic physiology of vitamin D. Pregnancy induces dramatic changes in regulation of vitamin D. The investigators hypothesize that increased maternal, placental, and fetal vitamin D requirements during late gestation will result in an increase in vitamin D absorption and a decrease in the half-life of both vitamin D3 and 25-hydroxyvitamin D. The fetus is entirely dependent on maternal vitamin D to meet its requirements for this nutrient. Maternal vitamin D is thought to be passively transferred across the placenta to the fetus given that neonatal concentrations of 25(OH)D are at least 20-30% lower than maternal 25(OH)D concentrations. To date, much of what is known about vitamin D absorption and utilization in humans has been extrapolated from early radiotracer studies in adult men and non-pregnant women and there are no in vivo data to determine if maternal vitamin D3 or maternal 25(OH)D3, or both, can be transferred across the placenta to the fetus
The specific aims of this project are to:
- To characterize the impact of pregnancy on the absorption of vitamin D3, conversion into 25(OH)D3, and serum half-life of 25OH)D3 in pregnant and non-pregnant women using tri-deuterated vitamin D3, state of the art UHPLC-MS/MS methodology and mathematical modeling.
- To study the impact of obesity on vitamin D kinetics and the D content of serum and adipose tissue in pregnant and non-pregnant women.
- To evaluate the impact of genetic ancestry on vitamin D kinetics and the D content of serum and adipose tissue in pregnant and non-pregnant women.
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 20 Years 至 39 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 否
入选标准
- 未提供
排除标准
- 未提供
结局指标
主要结局
Impact of pregnancy on serum vitamin D absorption
时间窗: Across 40 days study period
A baseline blood sample (20 mL) will be obtained for analysis of the baseline concentrations of indicators of vitamin D status. Each woman will be asked to ingest two pieces of toast onto which a dose of 35 μg of \[6,19,19-d3\]-vitamin D3 has been added. Women will return to the at 4 hour, 8 hour, Day 2, 10, 25, and 40 (± 2 days) for an additional blood sample (15 mL each) to assess the disappearance of the tri-deuterated D3, conversion into 25(OH)D3, and serum half-life of 25(OH)D3.
Impact of obesity on vitamin D absorption
时间窗: Across 40 days study period
A baseline blood sample (20 mL) will be obtained for analysis of the baseline concentrations of indicators of vitamin D status. Each woman will be asked to ingest two pieces of toast onto which a dose of 35 μg of \[6,19,19-d3\]-vitamin D3 has been added. Women will return to the at 4 hour, 8 hour, Day 2, 10, 25, and 40 (± 2 days) for an additional blood sample (15 mL each) to assess the disappearance of the tri-deuterated D3, conversion into 25(OH)D3, and serum half-life of 25(OH)D3. Body composition measure using Bioelectrical Impedance Analysis (BIA) will be conducted on Day 0 for all participants and Day 40 for he pregnant participants to obtain information on BMI and fat mass. Adipose tissue (\<1 gram) will be extracted using needle biopsy from the upper buttock area on all participants for D content analysis.
Impact of ancestry on serum vitamin D absorption
时间窗: Across 40 days study period
A baseline blood sample (20 mL) will be obtained for analysis of the baseline concentrations of calcitropic hormones and indicators of vitamin D status. Each woman will be asked to ingest one quarter piece of toast onto which a dose of 35 ug of \[6,19,19-d3\]-vitamin D3 has been added. Women will return to the at 4 hour, 8 hour, Day 1, 3, 10, 25, and 40 (± 2 days) for an additional blood sample (15 mL each) to assess the disappearance of the tri-deuterated D3, conversion into 25(OH)D3, and serum half-life of 25(OH)D3. DNA will be extracted to perform ancestry genotyping and determine vitamin D binding protein genotypes.
次要结局
- Placental protein quantification(Across 40 days study period)