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A Randomized Double-blind Placebo-controlled Trial of the Effect of Vitamin D Supplementation on Breast Density in Premenopausal Women

Phase 2
18 Years
55 Years
Open (Enrolling)
Breast Cancer

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Trial Information

A Randomized Double-blind Placebo-controlled Trial of the Effect of Vitamin D Supplementation on Breast Density in Premenopausal Women



- to determine whether adding oral supplementation with vitamin D3 (cholecalciferol) at
doses of 1,000, 2,000 and 3,000 IU/d to baseline total vitamin D intake over a period of 12
months reduces mammographic breast density among premenopausal women at moderate to high
risk of breast cancer who reside in the Quebec City area, Canada.


- to assess the net increase in 25(OH)D levels resulting from this vitamin D3

- to document the compliance with, and safety of, supplementation with tested doses of
vitamin D3 over one year.

OUTLINE This study is a double-blind, placebo-controlled, randomized trial among
premenopausal women who live in the Quebec City area and have ≥ 20% breast density at

The intervention consists of the addition, over baseline total vitamin D intake from food
and supplements, of three different doses of vitamin D3 (1000, 2000 or 3000 IU/day) for a
period of 12 months. There are four arms in the trial:

- Arm 1: 1,000 IU vitamin D3/d (1 tablet vitamin D 1000 IU + 2 tablets placebo);

- Arm 2: 2,000 IU vitamin D3/d (2 tablets vitamin D 1000 IU + 1 tablet placebo);

- Arm 3: 3,000 IU vitamin D3/d (3 tablets vitamin D 1000 IU);

- Arm 4: placebo (3 tablets placebo/d).

Vitamin D tablets (1000 IU tablets) and the placebo tablets are undistinguishable in size,
shape, color and taste, and are manufactured by the same company.

Inclusion Criteria:

- be premenopausal at baseline;

- have breast density of at least 20% at baseline;

- have normal baseline serum calcium (2,12-2,60 mmol/L) and serum creatinine (45-85

- agree to have her mammogram at 12 months of follow-up at the same mammography clinic
(same site) as the one where the mammogram at recruitment was done.

Exclusion Criteria:

- taking > 400 IU/day of supplemental vitamin D and refusing to reduce (≤ 400 IU/day)
or cease such intake;

- taking > 600 mg/day of supplemental calcium and refusing to reduce (≤ 600 mg/day) or
cease such intake;

- have contra-indications for use of vitamin D supplementation (hypersensitivity to
vitamin D or its analogues; a history of renal calculi or hypercalcemia,
hypervitaminosis D);

- taking medication suspected to interact with vitamin D: frequent use of antacids
containing magnesium or aluminium; regular use of anticonvulsants (phenytoin,
phenobarbital), digoxin, cholestyramine, colestipol, orlistat, mineral oil;

- have a personal history of breast cancer;

- have a personal history of cancer other than non-melanoma skin cancer within 5 last

- have had breast reduction or augmentation including breast implantation (or planning
to undergo such surgery during the trial);

- be pregnant or planning a pregnancy in the next year.

Type of Study:


Study Design:

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Prevention

Outcome Measure:

Mammographic breast density

Outcome Description:

Difference in breast density between baseline and at 12 months

Outcome Time Frame:

12 months

Safety Issue:


Principal Investigator

Jacques Brisson, M.D., Sc.D.

Investigator Role:

Principal Investigator

Investigator Affiliation:

Centre de recherche du CHU de Québec, et Faculté de médecine de l'Université Laval


Canada: Health Canada

Study ID:




Start Date:

October 2012

Completion Date:

December 2014

Related Keywords:

  • Breast Cancer
  • breast cancer
  • mammographic breast density
  • vitamin D
  • prevention
  • randomized controlled trial
  • Breast Neoplasms