Clinical trial · Interventional
Vitamin D and Mammographic Breast Density
A Randomized Double-blind Placebo-controlled Trial of the Effect of Vitamin D Supplementation on Breast Density in Premenopausal Women
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Summary
Brief summary (as posted)
There is some evidence that vitamin D could be used to reduce breast cancer risk. Randomized controlled trials would provide definitive evidence about this effect. However, trials with breast cancer as outcome are expensive and time-consuming. Use of surrogate outcomes has been advocated to accelerate progress in the identification of interventions that could prevent breast cancer. Mammographic breast density is one of the strongest breast cancer risk indicators and is already used as a surrogate outcome in several breast cancer prevention trials. The aim of this double-blind randomized controlled trial is to determine whether daily oral supplementation with vitamin D3 (1,000, 2,000 or 3,000 IU) over a period of 1 year reduces breast density in premenopausal women compared to placebo. A total of 376 women (94 per arm) who live in Quebec City will be recruited. Showing that vitamin D reduces breast density would provide strong support for the idea that vitamin D can be a safe and inexpensive approach for the prevention of breast cancer.
Conditions
Conditions (1)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Breast Cancer | Malignant Breast Neoplasm | CURATED_EXACT | 0.92 |
Interventions
Interventions (2)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| Placebo | Dietary Supplement | — | UNRESOLVED |
| Vitamin D3 | Dietary Supplement | — | UNRESOLVED |
Design
Arms and outcomes
Arms (4)
- type
- EXPERIMENTAL
- label
- Vitamin D3 (cholecalciferol) 1000 IU
- description
- Oral vitamin D3 (cholecalciferol) supplementation, 1000 IU daily, for 12 months
- interventionNames
- Dietary Supplement: Vitamin D3
- type
- EXPERIMENTAL
- label
- Vitamin D3 (cholecalciferol) 2000 IU
- description
- Oral vitamin D3 (cholecalciferol) supplementation, 2000 IU daily, for 12 months
- interventionNames
- Dietary Supplement: Vitamin D3
- type
- EXPERIMENTAL
- label
- Vitamin D3 (cholecalciferol) 3000 IU
- description
Eligibility
Eligibility (as posted)
- Sex
- Female
- Minimum age
- 18 Years
- Maximum age
- 55 Years
Show eligibility criteria text
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 μmol/L); * 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 years; * 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.
References
Publications (0)
Data not yet available