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Vitamin D Status and Metabolism in Human Pregnancy

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT03051867
Recruitment Status : Completed
First Posted : February 14, 2017
Last Update Posted : February 14, 2017
Sponsor:
Information provided by (Responsible Party):
Cornell University

Brief Summary:
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.

Condition or disease
Pregnancy

Detailed Description:

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

As a secondary analysis, this study uses biological samples obtained from pregnant and nonpregnant control women who participated in a 12-wk randomized controlled trial in 2009-2010 which featured two doses of choline (i.e., 480 or 930 mg choline/d) (NCT01127022) [8]. Throughout the controlled feeding period, 26 third-trimester pregnant women and 21 nonpregnant women (both reproductive groups aged > 21 y) in a good health status consumed equivalent intakes of vitamin D (511 IU/d), calcium (1.6 g/d) and phosphorus (1.9 g/d) from the study diet and prenatal multivitamin supplement (Pregnancy Plus; Fairhaven Health LLC) for ≥ 10 weeks.

Dependent variables:

  1. Blood biomarkers of vitamin D metabolism at week 0 (study-baseline) and week 10 (representing study-end)
  2. Placental biomarkers of vitamin D metabolism at delivery
  3. Markers of bone metabolism in maternal and fetal cord blood as well as maternal urine

Ethical considerations

The study protocol of the original RCT was approved by the Institutional Review Board for Human Study Participant Use at Cornell University and the Cayuga Medical Center where pregnant women delivered their babies. Informed consent was obtained from all participants before study entry, and the original study was registered at clinicaltrials.gov as NCT01127022. For this secondary analysis, deidentified data will be used.

Dissemination Findings

Findings from the present study will be reported in manuscripts that will be submitted for publication to a leading medical/nutrition journal in an appropriate field (i.e. nutrition, bone, placenta, and reproductive physiology). In addition, findings will be presented as abstracts, posters, and presentations at research conferences.

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Study Type : Observational
Actual Enrollment : 47 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Vitamin D Status and Metabolism in Pregnant and Nonpregnant Control Women Consuming Controlled and Equivalent Intakes of Vitamin D
Actual Study Start Date : January 15, 2009
Actual Primary Completion Date : December 18, 2010
Actual Study Completion Date : December 18, 2011

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Vitamin D
Drug Information available for: Vitamin D

Group/Cohort
Third-trimester pregnant women
Women differing in their reproductive state (pregnant versus nonpregnant) will consume equivalent dietary intakes of vitamin D and related nutrients as part of a feeding study.
Nonpregnant control women
Women differing in their reproductive state (pregnant versus nonpregnant) will consume equivalent dietary intakes of vitamin D and related nutrients as part of a feeding study.



Primary Outcome Measures :
  1. Maternal circulating concentrations of 25-hydroxyvitamin D [ Time Frame: 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.

  2. Maternal circulating concentrations of 1,25-dihydroxyvitamin D [ Time Frame: 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.

  3. Maternal circulating concentrations 24,25-dihydroxyvitamin D [ Time Frame: 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.

  4. Placental mRNA abundance of 25-hydroxylase [ Time Frame: 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.

  5. Placental mRNA abundance of 24-hydroxylase [ Time Frame: 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.

  6. Placental 25-hydroxyvitamin D [ Time Frame: 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.

  7. Placental 24,25-dihydroxyvitamin D [ Time Frame: 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.


Secondary Outcome Measures :
  1. Maternal circulating intact parathyroid hormone [ Time Frame: Baseline (week 0; 26-29 wk gestation) and study-end (week 10; 36-39 wk gestation) ]
    Plasma intact parathyroid hormone [iPTH] will be measured using an automated immunoassay, and the relationship of maternal serum 25(OH)D with maternal iPTH will be assessed using a linear mixed model which considers potential confounders.

  2. Maternal circulating carboxy-terminal cross-linking telopeptide of type 1 collagen [ Time Frame: Baseline (week 0; 26-29 wk gestation), study-end (week 10; 36-39 wk gestation), and delivery ]
    Plasma carboxy-terminal cross-linking telopeptide of type 1 collagen [CTx] will be measured using an ELISA kit, and the relationships of maternal serum 25(OH)D with maternal CTx will be assessed using a linear mixed model which considers potential confounders.

  3. Maternal urinary deoxypyridinoline/creatinine [ Time Frame: Baseline (week 0; 26-29 wk gestation), study-end (week 10; 36-39 wk gestation) ]
    Urinary deoxypyridinoline/creatinine [DPD/Cr] will be measured using an ELISA kit, and the relationships of maternal serum 25(OH)D with maternal DPD/Cr will be assessed using a linear mixed model which considers potential confounders.

  4. Maternal circulating osteocalcin [ Time Frame: Baseline (week 0; 26-29 wk gestation), study-end (week 10; 36-39 wk gestation), and delivery ]
    Plasma osteocalcin [OC] will be measured using an ELISA kit, and the relationships of maternal serum 25(OH)D with maternal OC will be assessed using a linear mixed model which considers potential confounders.


Biospecimen Retention:   Samples With DNA
blood, urine, cord blood, placental tissue


Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.


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Ages Eligible for Study:   21 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   Female
Gender Based Eligibility:   Yes
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
The study population consists of all healthy third-trimester pregnant (n=26) and nonpregnant (n=21) women who participated in the original RCT study.
Criteria

Inclusion Criteria:

  • 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)

Exclusion Criteria:

  • Use of tobacco, drug, or alcohol
  • Use of prescription medications known to affect liver function
  • Pregnancy associated complications

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03051867


Locations
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United States, New York
Human Metabolic Research Unit, Cornell University
Ithaca, New York, United States, 14853
Sponsors and Collaborators
Cornell University
Investigators
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Principal Investigator: Marie Caudill, PhD Cornell University
Publications:

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
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Responsible Party: Cornell University
ClinicalTrials.gov Identifier: NCT03051867    
Other Study ID Numbers: OSP 74161
First Posted: February 14, 2017    Key Record Dates
Last Update Posted: February 14, 2017
Last Verified: February 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No