Vitamin D Status and Metabolism in Pregnant and Nonpregnant Control Women Consuming Controlled and Equivalent Intakes of Vitamin D
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 47
- 试验地点
- 1
- 主要终点
- Maternal circulating concentrations of 25-hydroxyvitamin D
研究概览
简要总结
The purpose of the present study is to understand the effect of pregnancy on vitamin D metabolism and requirements as well as the modulatory role of the placenta in vitamin D metabolism during pregnancy. In addition, a human placental cell culture model will be employed to examine vitamin D metabolic flux in human trophoblast cells. The impact of maternal vitamin D status on maternal and fetal bone health during gestation will also be examined.
详细描述
Rationale
Despite mounting evidence that maternal vitamin D status is linked to pregnancy outcomes [1,2], the impact of pregnancy on vitamin D metabolism and requirement has yet to be clearly defined. In addition, although the placenta is known to express all components of the vitamin D metabolic pathway [3,4], very little is known about placental vitamin D metabolism. Moreover, although vitamin D is known to affect bone health in the nonpregnant state, the effect of maternal vitamin D status on maternal and fetal bone health in human pregnancy is unclear [5-7]. Therefore, the present study seeks to advance current understanding of vitamin D metabolism and requirements during pregnancy.
Objective and Research Questions
This study aims to examine: 1) the effect of pregnancy on a comprehensive panel of blood biomarkers of vitamin D status and metabolism; 2) the role of the placenta in modulating circulating vitamin D metabolites; and 3) the impact of maternal vitamin D status on maternal and fetal markers of bone metabolism.
Study Population, Design, and Exposure
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
- 21 Years 至 —（Adult, Older Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Age of 21-40 y
- •Healthiness as assessed by health-related questionnaire, a blood chemistry profile, and a complete blood count
- •Normal liver and kidney function
- •Willingness to comply with the study protocol
- •Singleton pregnancy (pregnant women only)
排除标准
- •Use of tobacco, drug, or alcohol
- •Use of prescription medications known to affect liver function
- •Pregnancy associated complications
结局指标
主要结局
Maternal circulating concentrations of 25-hydroxyvitamin D
时间窗: Baseline (week 0; 26-29 wk gestation) and study-end (week 10; 36-39 wk gestation)
Serum 25-hydroxyvitamin D \[25(OH)D\] will be measured using an isotope dilution LC-MS/MS methodology, and the effect of reproductive state on serum 25(OH)D will be examined using a linear mixed model which considers confounding factors.
Maternal circulating concentrations of 1,25-dihydroxyvitamin D
时间窗: Baseline (week 0; 26-29 wk gestation) and study-end (week 10; 36-39 wk gestation)
Plasma 1,25-dihydroxyvitamin D \[1,25(OH)2D\] will be measured using an EIA kit, and the effect of reproductive state on circulating 1,25(OH)2D will be examined using a linear mixed model which considers confounding factors.
Maternal circulating concentrations 24,25-dihydroxyvitamin D
时间窗: Baseline (week 0; 26-29 wk gestation) and study-end (week 10; 36-39 wk gestation)
Plasma 24,25-dihydroxyvitamin D \[24,25(OH)2D\] will be measured using an isotope dilution LC-MS/MS methodology, and the effect of reproductive state on circulating 24,25(OH)2D will be examined using a linear mixed model which considers potential confounders.
Placental mRNA abundance of 25-hydroxylase
时间窗: Delivery
Placental mRNA abundance of 25-hydroxylase \[CYP2R1\] will be measured using a qPCR, and the associations of placental CYP2R1 mRNA abundance with serum 25(OH)D will be examined using a linear mixed model which considers potential confounders.
Placental mRNA abundance of 24-hydroxylase
时间窗: Delivery
Placental mRNA abundance of 24-hydroxylase \[CYP24A1\] will be measured using a qPCR, and the associations of placental CYP24A1 mRNA abundance with circulating 24,25(OH)2D will be examined using a linear mixed model which considers potential confounders.
Placental 25-hydroxyvitamin D
时间窗: Delivery
25(OH)D will be measured from placental tissue using an isotope dilution LC-MS/MS methodology, and the associations of placental 25(OH)D with serum 25(OH)D as well as placental CYP2R1 mRNA abundance will be examined using a Pearson correlation test and a linear mixed model which considers potential confounders.
Placental 24,25-dihydroxyvitamin D
时间窗: Delivery
24,25(OH)2D will be measured from placental tissue using an isotope dilution LC-MS/MS methodology, and the associations of placental 24,25(OH)2D with circulating 25(OH)D and 24,25(OH)2D as well as placental CYP24A1 mRNA abundance will be examined using a Pearson correlation test and a linear mixed model which adjusts for potential confounders.
次要结局
- Maternal circulating carboxy-terminal cross-linking telopeptide of type 1 collagen(Baseline (week 0; 26-29 wk gestation), study-end (week 10; 36-39 wk gestation), and delivery)
- Maternal circulating intact parathyroid hormone(Baseline (week 0; 26-29 wk gestation) and study-end (week 10; 36-39 wk gestation))
- Maternal urinary deoxypyridinoline/creatinine(Baseline (week 0; 26-29 wk gestation), study-end (week 10; 36-39 wk gestation))
- Maternal circulating osteocalcin(Baseline (week 0; 26-29 wk gestation), study-end (week 10; 36-39 wk gestation), and delivery)