Inter-relationship Between Vitamin D Requirements and Calcium Intake in Older Adults

Vitamin D Deficiency Clinical Trial

— VitD-Ca  

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01990872
• Other study ID #: PR-IC-1111-10005
• Status: Completed
• Phase: N/A
• First received: November 8, 2013
• Last updated: November 21, 2013
• Start date: October 2012
• Est. completion date: November 2013

Study information

• Verified date: November 2013
• Source: University College Cork
• Contact: n/a
• Is FDA regulated: No
• Health authority: Ireland: Irish Medicines Board
• Study type: Interventional

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 125
• Est. completion date: November 2013
• Est. primary completion date: November 2013
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 50 Years to 80 Years

Eligibility

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 Design

Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Prevention

Related Conditions & MeSH terms

• Vitamin D Deficiency

Intervention

Dietary Supplement:
• Vitamin D3 (20 micrograms/day)
Vitamin D3 (20 micrograms/day)
• Placebo
Placebo (0 micrograms vitamin D3/day)

Locations

Country	Name	City	State
Ireland	Human Dietary Studies Facility, School of Food and Nutritional Sciences, University College Cork, Cork, Ireland	Cork

Sponsors (1)

Lead Sponsor	Collaborator
University College Cork

Country where clinical trial is conducted

Ireland, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Response of serum 25(OH)D concentration over winter in subjects stratified by calcium intake		0, 8, 15 weeks	No
Secondary	Serum albumin-adjusted calcium		0, 8, 15 weeks	Yes
Secondary	serum parathyroid hormone		0, 8, 15 weeks	No
Secondary	Serum 24,25(OH)2D		0 and 15 weeks	No
Secondary	Serum 1,25(OH)2D		0 and 15 weeks	No
Secondary	Serum free 25(OH)D		0 and 15 weeks	No
Secondary	Serum vitamin D binding protein		0 and 15 weeks	No