Vitamin D Supplementation in Older Women (VIDOS)

March 11, 2016 updated by: Creighton University

Determination of RDA for Vitamin D in Caucasian and African American Women

The purpose of this study is to examine the effects of several doses of vitamin D on hormones related to bone, calcium absorption, bone density and muscle strength.

Study Overview

Detailed Description

The prevalence of osteoporosis is high in the United States, with about 10 million people over the age of 50 already having the disease and another 34 million at risk for developing it. Development of low-cost and effective strategies is important for preventing osteoporosis and reducing osteoporotic fractures. A simple inexpensive strategy to prevent osteoporosis is adequate nutrition with calcium and vitamin D. Serum 25OHD (25-hydroxyvitamin D) is now accepted as the objective measure of vitamin D nutrition. There is a growing understanding that serum 25OHD concentrations of at least 30-32 ng/ml are needed for optimal bone health at which serum parathyroid hormone (PTH) concentrations reach a minimum.

There are no systematic prospective dose response studies aimed at determining the optimum amount of vitamin D intake required to maintain optimum serum 25OHD levels in the population which will help in determining the estimated average requirement (EAR) and recommended dietary requirement (RDA) for vitamin D. More work to determine the RDA for vitamin D has been recommended by the Panel on Calcium and Related Nutrients of the Food and Nutrition Board. This study is aimed at filling the information gap by concentrating on the high risk group of postmenopausal women. We are testing the theory that increasing serum 25OHD to a level greater than 30 ng/ml will reduce serum PTH in the high risk group of vitamin D insufficient postmenopausal women with an adequate intake of calcium. We also believe that the dose of vitamin D that will achieve this level is approximately 4400IU per day, which is well above the suggested adequate intake of 400-600 ID recommended for the elderly.

In a one year double blind, randomized prospective clinical trial, we will examine the dose response effect of supplementation with different doses of vitamin D3 (400, 800, 1600, 2400, 3200, 4000, 4800IU/day) on the primary outcomes of serum 25OHD and PTH in 160 postmenopausal Caucasian and 160 African American women who have inadequate vitamin D levels in winter. We expect that the results from this study will add useful and important information about the RDA for vitamin D for postmenopausal women who are more susceptible to osteoporosis. The results from this study will also help in designing future clinical trials to study the effect of vitamin D, for example in preventing fractures, falls, cancer.

The main objective of the current proposal is to study the effect of increasing doses of vitamin D3 in the high risk group of postmenopausal Caucasian and African American women with hypovitaminosis D (serum 25OHD <20 ng/ml) in winter in presence of sufficient calcium intake, in order to determine the Estimated Average Requirement (EAR) that covers 50% and the Recommended Daily allowance (RDA) covers 97.5% of population for vitamin D. We will use a serum 25OHD concentration equal >30 ng/ml and normalization of serum PTH as indicators of adequacy. We expect that the results from this proposal will add important information helpful in designing future larger clinical trials to determine the recommended dietary allowance (RDA) for vitamin D in other ethnic groups and designing clinical trials on the effect of vitamin D on falls and fractures.

We hypothesize that increasing serum 25OHD to a level greater than 30 ng/ml with vitamin D supplements in 97 percent of the study subjects will reduce serum PTH and bone markers to premenopausal range. We postulate that the RDA of vitamin D that will achieve a serum 25OHD of ≥ 30 ng/ml in 97.5% of women during winter is approximately 4400 IU/d and the EAR dose of vitamin D is between 800-1000 IU.

The specific aims of the proposal are,

  1. To examine the dose response effect of vitamin D3, 400, 800, 1600, 2400, 3200, 4000, and 4800 IU /d in postmenopausal Caucasian and African American women with hypovitaminosis D (serum 25OHD equal <20 ng/ml) in winter plus an adequate calcium intake compared to a calcium control group, on serum 25OHD and PTH levels, which constitute our primary outcome measures.
  2. To determine the EAR and RDA for postmenopausal women by establishing the dose of vitamin D3 that will increase serum 25OHD above 30 ng/ml in 97.5% of study subjects in winter and reduce serum PTH to the normal premenopausal range.
  3. To study the dose response effect of vitamin D3 on calcium absorption, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) serum calcium, serum bone markers, bone mineral density (BMD) and falls (only in elderly) (the secondary outcome measures)
  4. To establish the long term safety of these doses relating to hypercalcemia and hypercalciuria

Progress: Caucasian enrollment completed July 2008; African American enrollment completed May 2009

Study Type

Interventional

Enrollment (Actual)

273

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

    • Nebraska
      • Omaha, Nebraska, United States, 68131
        • Creighton University Medical Center

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

57 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • At least 7 years post-menopause
  • Serum 25OHD level 5 ng/ml to 20 ng/ml
  • BMI less than or equal to 40 kg/m2
  • Willing to discontinue multivitamins that contain vitamin D during the study

Exclusion Criteria:

  • Cancer (except basal cell carcinoma) or terminal illness
  • Previous hip fracture
  • Hemiplegia (paralysis of one side of the body)
  • Uncontrolled type I diabetes or fasting blood sugar greater than 140 mg in type II
  • Kidney stones more than twice in a lifetime
  • Chronic renal failure
  • Evidence of chronic liver disease, including alcoholism
  • Physical conditions such as severe osteoarthritis, rheumatoid arthritis, heart failure severe enough to prevent reasonable physical activity
  • Previous treatment with bisphosphonates (more that 3 months), PTH or PTH derivatives, (e.g. Teriparatide or Fluoride) in the last 6 months
  • Previous treatment within the last 6 months with calcitonin or estrogen
  • Chronic high dose corticosteroid therapy (more than 10 mg per day) for over 6 months and not within the last 6 months
  • Anticonvulsant therapy
  • High dose thiazide therapy (more than 37.5 mg)
  • 24 hour urine calcium greater than 290 mg on 2 baseline tests
  • Serum calcium exceeding upper normal limit on 2 baseline tests
  • Bone Mineral Density T-score less than -3.0 for spine or hip

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: vitamin D3 400 IU daily
Orally for one year
Orally for one year; dosage adjusted so that calcium intake is 1200-1400mg daily
Other Names:
  • Citracal
Experimental: vitamin D3 800 IU daily
Orally for one year
Orally for one year; dosage adjusted so that calcium intake is 1200-1400mg daily
Other Names:
  • Citracal
Experimental: vitamin D3 1600 IU daily
Orally for one year
Orally for one year; dosage adjusted so that calcium intake is 1200-1400mg daily
Other Names:
  • Citracal
Experimental: vitamin D3 2400 IU daily
Orally for one year
Orally for one year; dosage adjusted so that calcium intake is 1200-1400mg daily
Other Names:
  • Citracal
Experimental: vitamin D3 3200 IU daily
Orally for one year
Orally for one year; dosage adjusted so that calcium intake is 1200-1400mg daily
Other Names:
  • Citracal
Experimental: vitamin D3 4000 IU daily
Orally for one year
Orally for one year; dosage adjusted so that calcium intake is 1200-1400mg daily
Other Names:
  • Citracal
Experimental: vitamin D3 4800 IU daily
Orally for one year
Orally for one year; dosage adjusted so that calcium intake is 1200-1400mg daily
Other Names:
  • Citracal
Placebo Comparator: placebo
matched to vitamin D tablet
Orally for one year

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Changes in Serum 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) levels
Time Frame: Baseline, 6months,12 months
Baseline, 6months,12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Calcium absorption
Time Frame: Baseline and 12 months
100mg calcium+ calcium45
Baseline and 12 months
Serum/urine calcium
Time Frame: Baseline and every 3 months
Baseline and every 3 months
Bone markers
Time Frame: Baseline, and 12 months
Baseline, and 12 months
Bone density
Time Frame: Baseline and 12 months
spine,hip,total body,lateral
Baseline and 12 months
Muscle strength
Time Frame: Baseline,6 months,12 months
leg strength( Cybex),timed up and go,hand grip,chair stand,gait speed,quiet stance,postural stability( biodex),standing balance
Baseline,6 months,12 months
Falls
Time Frame: Baseline and every 3 months
questionnaire
Baseline and every 3 months
Pulmonary function studies
Time Frame: baseline and final test
FEV1
baseline and final test
Genotyping
Time Frame: one time
one time
Molecular studies of peripheral leucocytes
Time Frame: baseline and final test
baseline and final test
Adult Depression Score
Time Frame: baseline and 12 months
questionnaire
baseline and 12 months
Physical Activity Scale form ( PASE)
Time Frame: baseline,6 months,12 months
questionnaire
baseline,6 months,12 months
sun exposure
Time Frame: baseline and every 3 months
sun exposure form and skin color evaluation by a reflective meter (SmartProbe)
baseline and every 3 months
Basic metabolic panel
Time Frame: baseline and every 3 months
baseline and every 3 months
serum 1,25 dihydroxyvitamin D
Time Frame: baseline and 12 months
baseline and 12 months
quality of life
Time Frame: baseline and 12 months
questionnaire
baseline and 12 months

Collaborators and Investigators

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

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

April 1, 2007

Primary Completion (Actual)

August 1, 2011

Study Completion (Actual)

August 1, 2011

Study Registration Dates

First Submitted

May 10, 2007

First Submitted That Met QC Criteria

May 10, 2007

First Posted (Estimate)

May 14, 2007

Study Record Updates

Last Update Posted (Estimate)

March 14, 2016

Last Update Submitted That Met QC Criteria

March 11, 2016

Last Verified

March 1, 2016

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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