Inter-relationship Between Vitamin D Requirements and Calcium Intake in Older Adults (VitD-Ca)

November 21, 2013 updated by: Kevin D. Cashman, University College Cork

Randomized Controlled Trial to Explore the Inter-relationship Between Vitamin D Requirements and Calcium Intake

This winter-based placebo-controlled, single-dose vitamin D randomized controlled trial (RCT) aims to examine the impact of various levels of habitual calcium intake on dietary vitamin D requirements in older adults stratified by calcium intake. This will provide new data on the impact of different levels of calcium intake, ranging from low/moderate to high, on winter serum 25(OH)D levels, and their utilization and catabolism in adults.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The aim of this study is to perform a randomised controlled vitamin D3 intervention study in apparently healthy, free-living adults (aged 50+ y) to investigate whether different levels of habitual calcium intake, ranging from low-moderate to high, influence serum 25(OH)D concentrations and indices of vitamin D activation and catabolism during winter, when vitamin D intake is adequate versus inadequate.

This research will provide new data and scientific understanding in relation to the impact of different levels of dietary calcium intake on vitamin D requirements in the older adult population. As such, this new data will inform dietary reference values for vitamin D.

Study Type

Interventional

Enrollment (Actual)

125

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Ireland
      • Cork, Ireland
        • Human Dietary Studies Facility, School of Food and Nutritional Sciences, University College Cork, Cork, Ireland

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

50 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

Consenting white men and women aged ≥ 50 y

Exclusion Criteria:

  • Unwilling to discontinue consumption of vitamin D-containing supplements 4 wks before the initiation of the study and throughout the study.
  • Planning to take a winter vacation (during the course of the 15-wk intervention) to a location at which either the altitude or the latitude was predicted to result in significant cutaneous vitamin D synthesis from solar radiation (e.g., a winter sun coastal resort or a mountain ski resort)
  • Use of tanning facilities of any type.
  • Pregnancy or planning to become pregnant during the study
  • A severe medical illness,
  • hypercalcaemia,
  • Known intestinal malabsorption syndrome,
  • Excessive alcohol use,
  • Taking medications known to interfere with vitamin D metabolism

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo in high calcium group
Placebo + habitual dietary calcium intake (>1000 mg/d)
Dietary supplement: Placebo
Placebo (0 micrograms vitamin D3/day)
Active Comparator: Vitamin D3 in low/moderate calcium group
Vitamin D3 (20 microgram/day) + habitual calcium intake <700 mg/d
Dietary supplement: Vitamin D3 (20 micrograms/day)
Vitamin D3 (20 micrograms/day)
Placebo Comparator: Placebo in low/moderate calcium group
Placebo + habitual calcium intake <700 mg/d
Dietary supplement: Placebo
Placebo (0 micrograms vitamin D3/day)
Active Comparator: Vitamin D3 in high calcium group
Vitamin D3 (20 microgram/day) + habitual calcium intake (>1000 mg/d)
Dietary supplement: Vitamin D3 (20 micrograms/day)
Vitamin D3 (20 micrograms/day)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Response of serum 25(OH)D concentration over winter in subjects stratified by calcium intake
Time Frame: 0, 8, 15 weeks
0, 8, 15 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
Serum albumin-adjusted calcium
Time Frame: 0, 8, 15 weeks
0, 8, 15 weeks
serum parathyroid hormone
Time Frame: 0, 8, 15 weeks
0, 8, 15 weeks
Serum 24,25(OH)2D
Time Frame: 0 and 15 weeks
0 and 15 weeks
Serum 1,25(OH)2D
Time Frame: 0 and 15 weeks
0 and 15 weeks
Serum free 25(OH)D
Time Frame: 0 and 15 weeks
0 and 15 weeks
Serum vitamin D binding protein
Time Frame: 0 and 15 weeks
0 and 15 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University College Cork

Investigators

  • Principal Investigator: Kevin D Cashman, BSc. PhD, University College Cork

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

October 1, 2012

Primary Completion (Actual)

November 1, 2013

Study Completion (Actual)

November 1, 2013

Study Registration Dates

First Submitted

November 8, 2013

First Submitted That Met QC Criteria

November 21, 2013

First Posted (Estimate)

November 25, 2013

Study Record Updates

Last Update Posted (Estimate)

November 25, 2013

Last Update Submitted That Met QC Criteria

November 21, 2013

Last Verified

November 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PR-IC-1111-10005

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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