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Effect of vitamin D supplements on cancer and fracture risks

Researchers in Boston and Japan, reviewed the effects of vitamin D with or without calcium supplementation.

First, the details.

  • 19 studies (3 for cancer and 16 for fracture outcomes) and 28 observational studies (for cancer outcomes) were analyzed.
  • Data were combined for a meta-analysis.
  • Most patients were older (at least 65 years) postmenopausal women.

And, the results.

  • The results suggest that high-dose (1000 IU/day) vitamin D supplementation can reduce the risk for total cancer.
  • It’s possible that higher blood 25-hydroxyvitamin D (25-[OH]D) concentrations might be associated with increased risk for cancer.
    • Each 10-nmol/L increase in blood 25-(OH)D concentration was associated with a 6% reduced risk for colorectal cancer.
  • There was no statistically significant dose–response relationship for prostate and breast cancer.
  • The combination of vitamin D and calcium supplementation reduced fracture risk in older adults.
  • The effects differed according to where the study took place (institution, community).
  • 1 study reported adverse outcomes associated with supplementation, including increased risk for renal and urinary tract stones.

The bottom line?

The authors concluded, “Combined vitamin D and calcium supplementation can reduce fracture risk, but the effects may be smaller among community-dwelling older adults than among institutionalized elderly persons.”

They continue, “Appropriate dose and dosing regimens, however, require further study.”

Furthermore, “Evidence is not sufficiently robust to draw conclusions regarding the benefits or harms of vitamin D supplementation for the prevention of cancer.”

12/21/11 22:24 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.